summaryrefslogtreecommitdiff
path: root/kernel/trace/blktrace.c
AgeCommit message (Collapse)Author
2026-03-06Merge tag 'block-7.0-20260305' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux Pull block fixes from Jens Axboe: - NVMe pull request via Keith: - Improve quirk visibility and configurability (Maurizio) - Fix runtime user modification to queue setup (Keith) - Fix multipath leak on try_module_get failure (Keith) - Ignore ambiguous spec definitions for better atomics support (John) - Fix admin queue leak on controller reset (Ming) - Fix large allocation in persistent reservation read keys (Sungwoo Kim) - Fix fcloop callback handling (Justin) - Securely free DHCHAP secrets (Daniel) - Various cleanups and typo fixes (John, Wilfred) - Avoid a circular lock dependency issue in the sysfs nr_requests or scheduler store handling - Fix a circular lock dependency with the pcpu mutex and the queue freeze lock - Cleanup for bio_copy_kern(), using __bio_add_page() rather than the bio_add_page(), as adding a page here cannot fail. The exiting code had broken cleanup for the error condition, so make it clear that the error condition cannot happen - Fix for a __this_cpu_read() in preemptible context splat * tag 'block-7.0-20260305' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: block: use trylock to avoid lockdep circular dependency in sysfs nvme: fix memory allocation in nvme_pr_read_keys() block: use __bio_add_page in bio_copy_kern block: break pcpu_alloc_mutex dependency on freeze_lock blktrace: fix __this_cpu_read/write in preemptible context nvme-multipath: fix leak on try_module_get failure nvmet-fcloop: Check remoteport port_state before calling done callback nvme-pci: do not try to add queue maps at runtime nvme-pci: cap queue creation to used queues nvme-pci: ensure we're polling a polled queue nvme: fix memory leak in quirks_param_set() nvme: correct comment about nvme_ns_remove() nvme: stop setting namespace gendisk device driver data nvme: add support for dynamic quirk configuration via module parameter nvme: fix admin queue leak on controller reset nvme-fabrics: use kfree_sensitive() for DHCHAP secrets nvme: stop using AWUPF nvme: expose active quirks in sysfs nvme/host: fixup some typos
2026-03-02blktrace: fix __this_cpu_read/write in preemptible contextChaitanya Kulkarni
tracing_record_cmdline() internally uses __this_cpu_read() and __this_cpu_write() on the per-CPU variable trace_cmdline_save, and trace_save_cmdline() explicitly asserts preemption is disabled via lockdep_assert_preemption_disabled(). These operations are only safe when preemption is off, as they were designed to be called from the scheduler context (probe_wakeup_sched_switch() / probe_wakeup()). __blk_add_trace() was calling tracing_record_cmdline(current) early in the blk_tracer path, before ring buffer reservation, from process context where preemption is fully enabled. This triggers the following using blktests/blktrace/002: blktrace/002 (blktrace ftrace corruption with sysfs trace) [failed] runtime 0.367s ... 0.437s something found in dmesg: [ 81.211018] run blktests blktrace/002 at 2026-02-25 22:24:33 [ 81.239580] null_blk: disk nullb1 created [ 81.357294] BUG: using __this_cpu_read() in preemptible [00000000] code: dd/2516 [ 81.362842] caller is tracing_record_cmdline+0x10/0x40 [ 81.362872] CPU: 16 UID: 0 PID: 2516 Comm: dd Tainted: G N 7.0.0-rc1lblk+ #84 PREEMPT(full) [ 81.362877] Tainted: [N]=TEST [ 81.362878] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 81.362881] Call Trace: [ 81.362884] <TASK> [ 81.362886] dump_stack_lvl+0x8d/0xb0 ... (See '/mnt/sda/blktests/results/nodev/blktrace/002.dmesg' for the entire message) [ 81.211018] run blktests blktrace/002 at 2026-02-25 22:24:33 [ 81.239580] null_blk: disk nullb1 created [ 81.357294] BUG: using __this_cpu_read() in preemptible [00000000] code: dd/2516 [ 81.362842] caller is tracing_record_cmdline+0x10/0x40 [ 81.362872] CPU: 16 UID: 0 PID: 2516 Comm: dd Tainted: G N 7.0.0-rc1lblk+ #84 PREEMPT(full) [ 81.362877] Tainted: [N]=TEST [ 81.362878] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 81.362881] Call Trace: [ 81.362884] <TASK> [ 81.362886] dump_stack_lvl+0x8d/0xb0 [ 81.362895] check_preemption_disabled+0xce/0xe0 [ 81.362902] tracing_record_cmdline+0x10/0x40 [ 81.362923] __blk_add_trace+0x307/0x5d0 [ 81.362934] ? lock_acquire+0xe0/0x300 [ 81.362940] ? iov_iter_extract_pages+0x101/0xa30 [ 81.362959] blk_add_trace_bio+0x106/0x1e0 [ 81.362968] submit_bio_noacct_nocheck+0x24b/0x3a0 [ 81.362979] ? lockdep_init_map_type+0x58/0x260 [ 81.362988] submit_bio_wait+0x56/0x90 [ 81.363009] __blkdev_direct_IO_simple+0x16c/0x250 [ 81.363026] ? __pfx_submit_bio_wait_endio+0x10/0x10 [ 81.363038] ? rcu_read_lock_any_held+0x73/0xa0 [ 81.363051] blkdev_read_iter+0xc1/0x140 [ 81.363059] vfs_read+0x20b/0x330 [ 81.363083] ksys_read+0x67/0xe0 [ 81.363090] do_syscall_64+0xbf/0xf00 [ 81.363102] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 81.363106] RIP: 0033:0x7f281906029d [ 81.363111] Code: 31 c0 e9 c6 fe ff ff 50 48 8d 3d 66 63 0a 00 e8 59 ff 01 00 66 0f 1f 84 00 00 00 00 00 80 3d 41 33 0e 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec [ 81.363113] RSP: 002b:00007ffca127dd48 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 81.363120] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f281906029d [ 81.363122] RDX: 0000000000001000 RSI: 0000559f8bfae000 RDI: 0000000000000000 [ 81.363123] RBP: 0000000000001000 R08: 0000002863a10a81 R09: 00007f281915f000 [ 81.363124] R10: 00007f2818f77b60 R11: 0000000000000246 R12: 0000559f8bfae000 [ 81.363126] R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000000a [ 81.363142] </TASK> The same BUG fires from blk_add_trace_plug(), blk_add_trace_unplug(), and blk_add_trace_rq() paths as well. The purpose of tracing_record_cmdline() is to cache the task->comm for a given PID so that the trace can later resolve it. It is only meaningful when a trace event is actually being recorded. Ring buffer reservation via ring_buffer_lock_reserve() disables preemption, and preemption remains disabled until the event is committed :- __blk_add_trace() __trace_buffer_lock_reserve() __trace_buffer_lock_reserve() ring_buffer_lock_reserve() preempt_disable_notrace(); <--- With this fix blktests for blktrace pass: blktests (master) # ./check blktrace blktrace/001 (blktrace zone management command tracing) [passed] runtime 3.650s ... 3.647s blktrace/002 (blktrace ftrace corruption with sysfs trace) [passed] runtime 0.411s ... 0.384s Fixes: 7ffbd48d5cab ("tracing: Cache comms only after an event occurred") Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-21Convert 'alloc_obj' family to use the new default GFP_KERNEL argumentLinus Torvalds
This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21treewide: Replace kmalloc with kmalloc_obj for non-scalar typesKees Cook
This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-17Merge tag 'block-7.0-20260216' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux Pull more block updates from Jens Axboe: - Fix partial IOVA mapping cleanup in error handling - Minor prep series ignoring discard return value, as the inline value is always known - Ensure BLK_FEAT_STABLE_WRITES is set for drbd - Fix leak of folio in bio_iov_iter_bounce_read() - Allow IOC_PR_READ_* for read-only open - Another debugfs deadlock fix - A few doc updates * tag 'block-7.0-20260216' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: blk-mq: use NOIO context to prevent deadlock during debugfs creation blk-stat: convert struct blk_stat_callback to kernel-doc block: fix enum descriptions kernel-doc block: update docs for bio and bvec_iter block: change return type to void nvmet: ignore discard return value md: ignore discard return value block: fix partial IOVA mapping cleanup in blk_rq_dma_map_iova block: fix folio leak in bio_iov_iter_bounce_read() block: allow IOC_PR_READ_* ioctls with BLK_OPEN_READ drbd: always set BLK_FEAT_STABLE_WRITES
2026-02-16blk-mq: use NOIO context to prevent deadlock during debugfs creationYu Kuai
Creating debugfs entries can trigger fs reclaim, which can enter back into the block layer request_queue. This can cause deadlock if the queue is frozen. Previously, a WARN_ON_ONCE check was used in debugfs_create_files() to detect this condition, but it was racy since the queue can be frozen from another context at any time. Introduce blk_debugfs_lock()/blk_debugfs_unlock() helpers that combine the debugfs_mutex with memalloc_noio_save()/restore() to prevent fs reclaim from triggering block I/O. Also add blk_debugfs_lock_nomemsave() and blk_debugfs_unlock_nomemrestore() variants for callers that don't need NOIO protection (e.g., debugfs removal or read-only operations). Replace all raw debugfs_mutex lock/unlock pairs with these helpers, using the _nomemsave/_nomemrestore variants where appropriate. Reported-by: Yi Zhang <yi.zhang@redhat.com> Closes: https://lore.kernel.org/all/CAHj4cs9gNKEYAPagD9JADfO5UH+OiCr4P7OO2wjpfOYeM-RV=A@mail.gmail.com/ Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com> Closes: https://lore.kernel.org/all/aYWQR7CtYdk3K39g@shinmob/ Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-13Merge tag 'trace-v7.0' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing updates from Steven Rostedt: "User visible changes: - Add an entry into MAINTAINERS file for RUST versions of code There's now RUST code for tracing and static branches. To differentiate that code from the C code, add entries in for the RUST version (with "[RUST]" around it) so that the right maintainers get notified on changes. - New bitmask-list option added to tracefs When this is set, bitmasks in trace event are not displayed as hex numbers, but instead as lists: e.g. 0-5,7,9 instead of 0000015f - New show_event_filters file in tracefs Instead of having to search all events/*/*/filter for any active filters enabled in the trace instance, the file show_event_filters will list them so that there's only one file that needs to be examined to see if any filters are active. - New show_event_triggers file in tracefs Instead of having to search all events/*/*/trigger for any active triggers enabled in the trace instance, the file show_event_triggers will list them so that there's only one file that needs to be examined to see if any triggers are active. - Have traceoff_on_warning disable trace pintk buffer too Recently recording of trace_printk() could go to other trace instances instead of the top level instance. But if traceoff_on_warning triggers, it doesn't stop the buffer with trace_printk() and that data can easily be lost by being overwritten. Have traceoff_on_warning also disable the instance that has trace_printk() being written to it. - Update the hist_debug file to show what function the field uses When CONFIG_HIST_TRIGGERS_DEBUG is enabled, a hist_debug file exists for every event. This displays the internal data of any histogram enabled for that event. But it is lacking the function that is called to process one of its fields. This is very useful information that was missing when debugging histograms. - Up the histogram stack size from 16 to 31 Stack traces can be used as keys for event histograms. Currently the size of the stack that is stored is limited to just 16 entries. But the storage space in the histogram is 256 bytes, meaning that it can store up to 31 entries (plus one for the count of entries). Instead of letting that space go to waste, up the limit from 16 to 31. This makes the keys much more useful. - Fix permissions of per CPU file buffer_size_kb The per CPU file of buffer_size_kb was incorrectly set to read only in a previous cleanup. It should be writable. - Reset "last_boot_info" if the persistent buffer is cleared The last_boot_info shows address information of a persistent ring buffer if it contains data from a previous boot. It is cleared when recording starts again, but it is not cleared when the buffer is reset. The data is useless after a reset so clear it on reset too. Internal changes: - A change was made to allow tracepoint callbacks to have preemption enabled, and instead be protected by SRCU. This required some updates to the callbacks for perf and BPF. perf needed to disable preemption directly in its callback because it expects preemption disabled in the later code. BPF needed to disable migration, as its code expects to run completely on the same CPU. - Have irq_work wake up other CPU if current CPU is "isolated" When there's a waiter waiting on ring buffer data and a new event happens, an irq work is triggered to wake up that waiter. This is noisy on isolated CPUs (running NO_HZ_FULL). Trigger an IPI to a house keeping CPU instead. - Use proper free of trigger_data instead of open coding it in. - Remove redundant call of event_trigger_reset_filter() It was called immediately in a function that was called right after it. - Workqueue cleanups - Report errors if tracing_update_buffers() were to fail. - Make the enum update workqueue generic for other parts of tracing On boot up, a work queue is created to convert enum names into their numbers in the trace event format files. This work queue can also be used for other aspects of tracing that takes some time and shouldn't be called by the init call code. The blk_trace initialization takes a bit of time. Have the initialization code moved to the new tracing generic work queue function. - Skip kprobe boot event creation call if there's no kprobes defined on cmdline The kprobe initialization to set up kprobes if they are defined on the cmdline requires taking the event_mutex lock. This can be held by other tracing code doing initialization for a long time. Since kprobes added to the kernel command line need to be setup immediately, as they may be tracing early initialization code, they cannot be postponed in a work queue and must be setup in the initcall code. If there's no kprobe on the kernel cmdline, there's no reason to take the mutex and slow down the boot up code waiting to get the lock only to find out there's nothing to do. Simply exit out early if there's no kprobes on the kernel cmdline. If there are kprobes on the cmdline, then someone cares more about tracing over the speed of boot up. - Clean up the trigger code a bit - Move code out of trace.c and into their own files trace.c is now over 11,000 lines of code and has become more difficult to maintain. Start splitting it up so that related code is in their own files. Move all the trace_printk() related code into trace_printk.c. Move the __always_inline stack functions into trace.h. Move the pid filtering code into a new trace_pid.c file. - Better define the max latency and snapshot code The latency tracers have a "max latency" buffer that is a copy of the main buffer and gets swapped with it when a new high latency is detected. This keeps the trace up to the highest latency around where this max_latency buffer is never written to. It is only used to save the last max latency trace. A while ago a snapshot feature was added to tracefs to allow user space to perform the same logic. It could also enable events to trigger a "snapshot" if one of their fields hit a new high. This was built on top of the latency max_latency buffer logic. Because snapshots came later, they were dependent on the latency tracers to be enabled. In reality, the latency tracers depend on the snapshot code and not the other way around. It was just that they came first. Restructure the code and the kconfigs to have the latency tracers depend on snapshot code instead. This actually simplifies the logic a bit and allows to disable more when the latency tracers are not defined and the snapshot code is. - Fix a "false sharing" in the hwlat tracer code The loop to search for latency in hardware was using a variable that could be changed by user space for each sample. If the user change this variable, it could cause a bus contention, and reading that variable can show up as a large latency in the trace causing a false positive. Read this variable at the start of the sample with a READ_ONCE() into a local variable and keep the code from sharing cache lines with readers. - Fix function graph tracer static branch optimization code When only one tracer is defined for function graph tracing, it uses a static branch to call that tracer directly. When another tracer is added, it goes into loop logic to call all the registered callbacks. The code was incorrect when going back to one tracer and never re-enabled the static branch again to do the optimization code. - And other small fixes and cleanups" * tag 'trace-v7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (46 commits) function_graph: Restore direct mode when callbacks drop to one tracing: Fix indentation of return statement in print_trace_fmt() tracing: Reset last_boot_info if ring buffer is reset tracing: Fix to set write permission to per-cpu buffer_size_kb tracing: Fix false sharing in hwlat get_sample() tracing: Move d_max_latency out of CONFIG_FSNOTIFY protection tracing: Better separate SNAPSHOT and MAX_TRACE options tracing: Add tracer_uses_snapshot() helper to remove #ifdefs tracing: Rename trace_array field max_buffer to snapshot_buffer tracing: Move pid filtering into trace_pid.c tracing: Move trace_printk functions out of trace.c and into trace_printk.c tracing: Use system_state in trace_printk_init_buffers() tracing: Have trace_printk functions use flags instead of using global_trace tracing: Make tracing_update_buffers() take NULL for global_trace tracing: Make printk_trace global for tracing system tracing: Move ftrace_trace_stack() out of trace.c and into trace.h tracing: Move __trace_buffer_{un}lock_*() functions to trace.h tracing: Make tracing_selftest_running global to the tracing subsystem tracing: Make tracing_disabled global for tracing system tracing: Clean up use of trace_create_maxlat_file() ...
2026-02-06blktrace: Make init_blk_tracer() asynchronousYaxiong Tian
The init_blk_tracer() function causes significant boot delay as it waits for the trace_event_sem lock held by trace_event_update_all(). Specifically, its child function register_trace_event() requires this lock, which is occupied for an extended period during boot. To resolve this, the execution of primary init_blk_tracer() is moved to the trace_init_wq workqueue, allowing it to run asynchronously, and prevent blocking the main boot thread. Link: https://patch.msgid.link/20260204015353.163331-1-tianyaxiong@kylinos.cn Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Yaxiong Tian <tianyaxiong@kylinos.cn> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2026-02-03block: don't use strcpy to copy blockdev nameJohannes Thumshirn
0-day bot flagged the use of strcpy() in blk_trace_setup(), because the source buffer can theoretically be bigger than the destination buffer. While none of the current callers pass a string bigger than BLKTRACE_BDEV_SIZE, use strscpy() to prevent eventual future misuse and silence the checker warnings. Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/r/202602020718.GUEIRyG9-lkp@intel.com/ Fixes: 113cbd62824a ("blktrace: pass blk_user_trace2 to setup functions") Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-12-05Merge tag 'trace-v6.19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing updates from Steven Rostedt: - Extend tracing option mask to 64 bits The trace options were defined by a 32 bit variable. This limits the tracing instances to have a total of 32 different options. As that limit has been hit, and more options are being added, increase the option mask to a 64 bit number, doubling the number of options available. As this is required for the kprobe topic branches as well as the tracing topic branch, a separate branch was created and merged into both. - Make trace_user_fault_read() available for the rest of tracing The function trace_user_fault_read() is used by trace_marker file read to allow reading user space to be done fast and without locking or allocations. Make this available so that the system call trace events can use it too. - Have system call trace events read user space values Now that the system call trace events callbacks are called in a faultable context, take advantage of this and read the user space buffers for various system calls. For example, show the path name of the openat system call instead of just showing the pointer to that path name in user space. Also show the contents of the buffer of the write system call. Several system call trace events are updated to make tracing into a light weight strace tool for all applications in the system. - Update perf system call tracing to do the same - And a config and syscall_user_buf_size file to control the size of the buffer Limit the amount of data that can be read from user space. The default size is 63 bytes but that can be expanded to 165 bytes. - Allow the persistent ring buffer to print system calls normally The persistent ring buffer prints trace events by their type and ignores the print_fmt. This is because the print_fmt may change from kernel to kernel. As the system call output is fixed by the system call ABI itself, there's no reason to limit that. This makes reading the system call events in the persistent ring buffer much nicer and easier to understand. - Add options to show text offset to function profiler The function profiler that counts the number of times a function is hit currently lists all functions by its name and offset. But this becomes ambiguous when there are several functions with the same name. Add a tracing option that changes the output to be that of '_text+offset' instead. Now a user space tool can use this information to map the '_text+offset' to the unique function it is counting. - Report bad dynamic event command If a bad command is passed to the dynamic_events file, report it properly in the error log. - Clean up tracer options Clean up the tracer option code a bit, by removing some useless code and also using switch statements instead of a series of if statements. - Have tracing options be instance specific Tracers can have their own options (function tracer, irqsoff tracer, function graph tracer, etc). But now that the same tracer can be enabled in multiple trace instances, their options are still global. The API is per instance, thus changing one affects other instances. This isn't even consistent, as the option take affect differently depending on when an tracer started in an instance. Make the options for instances only affect the instance it is changed under. - Optimize pid_list lock contention Whenever the pid_list is read, it uses a spin lock. This happens at every sched switch. Taking the lock at sched switch can be removed by instead using a seqlock counter. - Clean up the trace trigger structures The trigger code uses two different structures to implement a single tigger. This was due to trying to reuse code for the two different types of triggers (always on trigger, and count limited trigger). But by adding a single field to one structure, the other structure could be absorbed into the first structure making he code easier to understand. - Create a bulk garbage collector for trace triggers If user space has triggers for several hundreds of events and then removes them, it can take several seconds to complete. This is because each removal calls tracepoint_synchronize_unregister() that can take hundreds of milliseconds to complete. Instead, create a helper thread that will do the clean up. When a trigger is removed, it will create the kthread if it isn't already created, and then add the trigger to a llist. The kthread will take the items off the llist, call tracepoint_synchronize_unregister(), and then remove the items it took off. It will then check if there's more items to free before sleeping. This makes user space removing all these triggers to finish in less than a second. - Allow function tracing of some of the tracing infrastructure code Because the tracing code can cause recursion issues if it is traced by the function tracer the entire tracing directory disables function tracing. But not all of tracing causes issues if it is traced. Namely, the event tracing code. Add a config that enables some of the tracing code to be traced to help in debugging it. Note, when this is enabled, it does add noise to general function tracing, especially if events are enabled as well (which is a common case). - Add boot-time backup instance for persistent buffer The persistent ring buffer is used mostly for kernel crash analysis in the field. One issue is that if there's a crash, the data in the persistent ring buffer must be read before tracing can begin using it. This slows down the boot process. Once tracing starts in the persistent ring buffer, the old data must be freed and the addresses no longer match and old events can't be in the buffer with new events. Create a way to create a backup buffer that copies the persistent ring buffer at boot up. Then after a crash, the always on tracer can begin immediately as well as the normal boot process while the crash analysis tooling uses the backup buffer. After the backup buffer is finished being read, it can be removed. - Enable function graph args and return address options at the same time Currently the when reading of arguments in the function graph tracer is enabled, the option to record the parent function in the entry event can not be enabled. Update the code so that it can. - Add new struct_offset() helper macro Add a new macro that takes a pointer to a structure and a name of one of its members and it will return the offset of that member. This allows the ring buffer code to simplify the following: From: size = struct_size(entry, buf, cnt - sizeof(entry->id)); To: size = struct_offset(entry, id) + cnt; There should be other simplifications that this macro can help out with as well * tag 'trace-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (42 commits) overflow: Introduce struct_offset() to get offset of member function_graph: Enable funcgraph-args and funcgraph-retaddr to work simultaneously tracing: Add boot-time backup of persistent ring buffer ftrace: Allow tracing of some of the tracing code tracing: Use strim() in trigger_process_regex() instead of skip_spaces() tracing: Add bulk garbage collection of freeing event_trigger_data tracing: Remove unneeded event_mutex lock in event_trigger_regex_release() tracing: Merge struct event_trigger_ops into struct event_command tracing: Remove get_trigger_ops() and add count_func() from trigger ops tracing: Show the tracer options in boot-time created instance ftrace: Avoid redundant initialization in register_ftrace_direct tracing: Remove unused variable in tracing_trace_options_show() fgraph: Make fgraph_no_sleep_time signed tracing: Convert function graph set_flags() to use a switch() statement tracing: Have function graph tracer option sleep-time be per instance tracing: Move graph-time out of function graph options tracing: Have function graph tracer option funcgraph-irqs be per instance trace/pid_list: optimize pid_list->lock contention tracing: Have function graph tracer define options per instance tracing: Have function tracer define options per instance ...
2025-11-04tracing: Allow tracer to add more than 32 optionsMasami Hiramatsu (Google)
Since enum trace_iterator_flags is 32bit, the max number of the option flags is limited to 32 and it is fully used now. To add a new option, we need to expand it. So replace the TRACE_ITER_##flag with TRACE_ITER(flag) macro which is 64bit bitmask. Link: https://lore.kernel.org/all/176187877103.994619.166076000668757232.stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2025-11-03blktrace: add support for REQ_OP_WRITE_ZEROES tracingChaitanya Kulkarni
Currently, REQ_OP_WRITE_ZEROES operations are not handled in the blktrace infrastructure, resulting in incorrect or missing operation labels in ftrace blktrace output. This manifests as write-zeroes operations appearing with incorrect labels like "N" instead of a proper "WZ" designation. This patch adds complete support for REQ_OP_WRITE_ZEROES across the blktrace infrastructure: Add BLK_TC_WRITE_ZEROES trace category in blktrace_api.h and update BLK_TC_END_V2 marker accordingly Map REQ_OP_WRITE_ZEROES to BLK_TC_WRITE_ZEROES in __blk_add_trace() to ensure proper trace event categorization Update fill_rwbs() to generate "WZ" label for write-zeroes operations in ftrace output, making them easily identifiable Add "write-zeroes" string mapping in act_to_str array for debugfs filter interface Update blk_fill_rwbs() to handle REQ_OP_WRITE_ZEROES for block layer event tracing With this fix, write-zeroes operations are now correctly traced and displayed. =========================================================== BEFORE THIS PATCH =========================================================== blkdiscard -z -o 0 -l 40960 /dev/nvme0n1 blkdiscard-3809 [030] ..... 1212.253701: block_bio_queue: 259,0 NS 0 + 80 [blkdiscard] blkdiscard-3809 [030] ..... 1212.253703: block_getrq: 259,0 NS 0 + 80 [blkdiscard] blkdiscard-3809 [030] ..... 1212.253704: block_io_start: 259,0 NS 40960 () 0 + 80 be,0,4 [blkdiscard] blkdiscard-3809 [030] ..... 1212.253704: block_plug: [blkdiscard] blkdiscard-3809 [030] ..... 1212.253706: block_unplug: [blkdiscard] 1 blkdiscard-3809 [030] ..... 1212.253706: block_rq_insert: 259,0 NS 40960 () 0 + 80 be,0,4 [blkdiscard] kworker/30:1H-566 [030] ..... 1212.253726: block_rq_issue: 259,0 NS 40960 () 0 + 80 be,0,4 [kworker/30:1H] <idle>-0 [030] d.h1. 1212.253957: block_rq_complete: 259,0 NS () 0 + 80 be,0,4 [0] <idle>-0 [030] dNh1. 1212.253960: block_io_done: 259,0 NS 0 () 0 + 0 none,0,0 [swapper/30] Trace Event Breakdown: Event | Device | Op | Sector | Sectors | Byte Size | Calculation block_bio_queue | 259,0 | NS | 0 | 80 | - | 80 × 512 = 40,960 block_getrq | 259,0 | NS | 0 | 80 | - | 80 × 512 = 40,960 block_io_start | 259,0 | NS | 0 | 80 | 40960 | Direct from trace block_rq_insert | 259,0 | NS | 0 | 80 | 40960 | Direct from trace block_rq_issue | 259,0 | NS | 0 | 80 | 40960 | Direct from trace block_rq_complete | 259,0 | NS | 0 | 80 | - | 80 × 512 = 40,960 block_io_done | 259,0 | NS | 0 | 0 | 0 | Completion (no data) Total Bytes Transferred: Sectors: 80 Bytes: 80 × 512 = 40,960 bytes =========================================================== AFTER THIS PATCH =========================================================== blkdiscard -z -o 0 -l 40960 /dev/nvme0n1 blkdiscard-2477 [020] ..... 960.989131: block_bio_queue: 259,0 WZS 0 + 80 [blkdiscard] blkdiscard-2477 [020] ..... 960.989134: block_getrq: 259,0 WZS 0 + 80 [blkdiscard] blkdiscard-2477 [020] ..... 960.989135: block_io_start: 259,0 WZS 40960 () 0 + 80 be,0,4 [blkdiscard] blkdiscard-2477 [020] ..... 960.989138: block_plug: [blkdiscard] blkdiscard-2477 [020] ..... 960.989140: block_unplug: [blkdiscard] 1 blkdiscard-2477 [020] ..... 960.989141: block_rq_insert: 259,0 WZS 40960 () 0 + 80 be,0,4 [blkdiscard] kworker/20:1H-736 [020] ..... 960.989166: block_rq_issue: 259,0 WZS 40960 () 0 + 80 be,0,4 [kworker/20:1H] <idle>-0 [020] d.h1. 960.989476: block_rq_complete: 259,0 WZS () 0 + 80 be,0,4 [0] <idle>-0 [020] dNh1. 960.989482: block_io_done: 259,0 WZS 0 () 0 + 0 none,0,0 [swapper/20] Trace Event Breakdown: Event | Device | Op | Sector | Sectors | Byte Size | Calculation block_bio_queue | 259,0 | WZS | 0 | 80 | - | 80 × 512 = 40,960 block_getrq | 259,0 | WZS | 0 | 80 | - | 80 × 512 = 40,960 block_io_start | 259,0 | WZS | 0 | 80 | 40960 | Direct from trace block_rq_insert | 259,0 | WZS | 0 | 80 | 40960 | Direct from trace block_rq_issue | 259,0 | WZS | 0 | 80 | 40960 | Direct from trace block_rq_complete | 259,0 | WZS | 0 | 80 | - | 80 × 512 = 40,960 block_io_done | 259,0 | WZS | 0 | 0 | 0 | Completion (no data) Total Bytes Transferred: Sectors: 80 Bytes: 80 × 512 = 40,960 bytes Tested with ftrace blktrace on NVMe devices using blkdiscard with the -z (write-zeroes) flag. Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-28blktrace: for ftrace use correct trace format verChaitanya Kulkarni
The ftrace blktrace path allocates buffers and writes trace events but was using the wrong recording function. After commit 4d8bc7bd4f73 ("blktrace: move ftrace blk_io_tracer to blk_io_trace2"), the ftrace interface was moved to use blk_io_trace2 format, but __blk_add_trace() still called record_blktrace_event() which writes in blk_io_trace (v1) format. This causes critical data corruption: - blk_io_trace (v1) has 32-bit 'action' field at offset 28 - blk_io_trace2 (v2) has 32-bit 'pid' at offset 28 and 64-bit 'action' at offset 32 - When record_blktrace_event() writes to a v2 buffer: * Writing pid (offset 32 in v1) corrupts the v2 action field * Writing action (offset 28 in v1) corrupts the v2 pid field * The 64-bit action is truncated to 32-bit via lower_32_bits() Fix by: 1. Adding version switch to select correct format (v1 vs v2) 2. Calling appropriate recording function based on version 3. Defaulting to v2 for ftrace (as intended by commit 4d8bc7bd4f73) 4. Adding WARN_ONCE for unexpected version values Without this patch :- linux-block (for-next) # sh reproduce_blktrace_bug.sh dd-14242 [033] d..1. 3903.022308: Unknown action 36a2 dd-14242 [033] d..1. 3903.022333: Unknown action 36a2 dd-14242 [033] d..1. 3903.022365: Unknown action 36a2 dd-14242 [033] d..1. 3903.022366: Unknown action 36a2 dd-14242 [033] d..1. 3903.022369: Unknown action 36a2 The action field is corrupted because: - ftrace allocated blk_io_trace2 buffer (64 bytes) - But called record_blktrace_event() (writes v1, 48 bytes) - Field offsets don't match, causing corruption The hex value shown 0x30e3 is actually a PID, not an action code! linux-block (for-next) # linux-block (for-next) # linux-block (for-next) # sh reproduce_blktrace_bug.sh Trace output looks correct: dd-2420 [019] d..1. 59.641742: 251,0 Q RS 0 + 8 [dd] dd-2420 [019] d..1. 59.641775: 251,0 G RS 0 + 8 [dd] dd-2420 [019] d..1. 59.641784: 251,0 P N [dd] dd-2420 [019] d..1. 59.641785: 251,0 U N [dd] 1 dd-2420 [019] d..1. 59.641788: 251,0 D RS 0 + 8 [dd] Fixes: 4d8bc7bd4f73 ("blktrace: move ftrace blk_io_tracer to blk_io_trace2") Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-28blktrace: use debug print to report dropped eventsChaitanya Kulkarni
The WARN_ON_ONCE introduced in commit f9ee38bbf70f ("blktrace: add block trace commands for zone operations") triggers kernel warnings when zone operations are traced with blktrace version 1. This can spam the kernel log during normal operation with zoned block devices when userspace is using the legacy blktrace protocol. Currently blktrace implementation drops newly added REQ_OP_ZONE_XXX when blktrace userspce version is set to 1. Remove the WARN_ON_ONCE and quietly filter these events. Add a rate-limited debug message to help diagnose potential issues without flooding the kernel log. The debug message can be enabled via dynamic debug when needed for troubleshooting. This approach is more appropriate as encountering zone operations with blktrace v1 is an expected condition that should be handled gracefully rather than warned about, since users may be running older blktrace userspace tools that only support version 1 of the protocol. With this patch :- linux-block (for-next) # git log -1 commit c8966006a0971d2b4bf94c0426eb7e4407c6853f (HEAD -> for-next) Author: Chaitanya Kulkarni <ckulkarnilinux@gmail.com> Date: Mon Oct 27 19:26:53 2025 -0700 blktrace: use debug print to report dropped events linux-block (for-next) # cdblktests blktests (master) # ./check blktrace blktrace/001 (blktrace zone management command tracing) [passed] runtime 3.805s ... 3.889s blktests (master) # dmesg -c blktests (master) # echo "file kernel/trace/blktrace.c +p" > /sys/kernel/debug/dynamic_debug/control blktests (master) # ./check blktrace blktrace/001 (blktrace zone management command tracing) [passed] runtime 3.889s ... 3.881s blktests (master) # dmesg -c [ 77.826237] blktrace: blktrace v1 cannot trace zone operation 0x1000190001 [ 77.826260] blktrace: blktrace v1 cannot trace zone operation 0x1000190004 [ 77.826282] blktrace: blktrace v1 cannot trace zone operation 0x1001490007 [ 77.826288] blktrace: blktrace v1 cannot trace zone operation 0x1001890008 [ 77.826343] blktrace: blktrace v1 cannot trace zone operation 0x1000190001 [ 77.826347] blktrace: blktrace v1 cannot trace zone operation 0x1000190004 [ 77.826350] blktrace: blktrace v1 cannot trace zone operation 0x1001490007 [ 77.826354] blktrace: blktrace v1 cannot trace zone operation 0x1001890008 [ 77.826373] blktrace: blktrace v1 cannot trace zone operation 0x1000190001 [ 77.826377] blktrace: blktrace v1 cannot trace zone operation 0x1000190004 blktests (master) # echo "file kernel/trace/blktrace.c -p" > /sys/kernel/debug/dynamic_debug/control blktests (master) # ./check blktrace blktrace/001 (blktrace zone management command tracing) [passed] runtime 3.881s ... 3.824s blktests (master) # dmesg -c blktests (master) # Reported-by: syzbot+153e64c0aa875d7e4c37@syzkaller.appspotmail.com Fixes: f9ee38bbf70f ("blktrace: add block trace commands for zone operations") Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: handle BLKTRACESETUP2 ioctlJohannes Thumshirn
Handle the BLKTRACESETUP2 ioctl, requesting an extended version of the blktrace protocol from user-space. Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: trace zone write plugging operationsJohannes Thumshirn
Trace zone write plugging operations on block devices. As tracing of zoned block commands needs the upper 32bit of the widened 64bit action, only add traces to blktrace if user-space has requested version 2 of the blktrace protocol. Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: expose ZONE APPEND completions to blktraceJohannes Thumshirn
Expose ZONE APPEND completions as a block trace completion action to blktrace. As tracing of zoned block commands needs the upper 32bit of the widened 64bit action, only add traces to blktrace if user-space has requested version 2 of the blktrace protocol. Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: add block trace commands for zone operationsJohannes Thumshirn
Add block trace commands for zone operations. These commands can only be handled with version 2 of the blktrace protocol. For version 1, warn if a command that does not fit into the 16 bits reserved for the command in this version is passed in. Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: move ftrace blk_io_tracer to blk_io_trace2Johannes Thumshirn
Move ftrace's blk_io_tracer to the new blk_io_trace2 infrastructure. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: move trace_note to blk_io_trace2Johannes Thumshirn
Move trace_note() to the new blk_io_trace2 infrastructure. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: differentiate between blk_io_trace versionsJohannes Thumshirn
Differentiate between blk_io_trace and blk_io_trace2 when relaying to user-space depending on which version has been requested by the blktrace utility. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: add definitions for struct blk_io_trace2Johannes Thumshirn
Add definitions for the extended version of the blktrace protocol using a wider action type to be able to record new actions in the kernel. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: pass blk_user_trace2 to setup functionsJohannes Thumshirn
Pass struct blk_user_trace_setup2 to blktrace_setup_finalize(). This prepares for the incoming extension of the blktrace protocol with a 64bit act_mask. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: add definitions for blk_user_trace_setup2Johannes Thumshirn
Add definitions for a version 2 of the blk_user_trace_setup ioctl. This new ioctl will enable a different struct layout of the binary data passed to user-space when using a new version of the blktrace utility requesting the new struct layout. Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: split do_blk_trace_setup into two functionsJohannes Thumshirn
Split do_blk_trace_setup into two functions, this is done to prepare for an incoming new BLKTRACESETUP2 ioctl(2) which can receive extended parameters from user-space. Also move the size verification logic to the callers in preparation for using a new internal structure later. Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: change the internal action to 64bitJohannes Thumshirn
Change the internal use of the action in blktrace to 64bit. Although for now only the lower 32bits will be used. With the upcoming version 2 of the blktrace user-space protocol the upper 32bit will also be utilized. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: untangle if/else sequence in __blk_add_traceJohannes Thumshirn
Untangle the if/else sequence setting the trace action in __blk_add_trace() and turn it into a switch statement for better extensibility. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: split out relaying a blktrace eventJohannes Thumshirn
Split out the code relaying a blktrace event to user-space using relayfs. This enables adding a second version supporting a new version of the protocol. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: factor out recording a blktrace eventJohannes Thumshirn
Factor out the recording of a blktrace event into its own function, deduplicating the code. This also enables recording different versions of the blktrace protocol later on. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22blktrace: only calculate trace length onceJohannes Thumshirn
De-duplicate the calculation of the trace length instead of doing the calculation twice, once for calling trace_buffer_lock_reserve() and once for calling relay_reserve(). Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-03Merge tag 'mm-nonmm-stable-2025-08-03-12-47' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: "Significant patch series in this pull request: - "squashfs: Remove page->mapping references" (Matthew Wilcox) gets us closer to being able to remove page->mapping - "relayfs: misc changes" (Jason Xing) does some maintenance and minor feature addition work in relayfs - "kdump: crashkernel reservation from CMA" (Jiri Bohac) switches us from static preallocation of the kdump crashkernel's working memory over to dynamic allocation. So the difficulty of a-priori estimation of the second kernel's needs is removed and the first kernel obtains extra memory - "generalize panic_print's dump function to be used by other kernel parts" (Feng Tang) implements some consolidation and rationalization of the various ways in which a failing kernel splats information at the operator * tag 'mm-nonmm-stable-2025-08-03-12-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (80 commits) tools/getdelays: add backward compatibility for taskstats version kho: add test for kexec handover delaytop: enhance error logging and add PSI feature description samples: Kconfig: fix spelling mistake "instancess" -> "instances" fat: fix too many log in fat_chain_add() scripts/spelling.txt: add notifer||notifier to spelling.txt xen/xenbus: fix typo "notifer" net: mvneta: fix typo "notifer" drm/xe: fix typo "notifer" cxl: mce: fix typo "notifer" KVM: x86: fix typo "notifer" MAINTAINERS: add maintainers for delaytop ucount: use atomic_long_try_cmpxchg() in atomic_long_inc_below() ucount: fix atomic_long_inc_below() argument type kexec: enable CMA based contiguous allocation stackdepot: make max number of pools boot-time configurable lib/xxhash: remove unused functions init/Kconfig: restore CONFIG_BROKEN help text lib/raid6: update recov_rvv.c zero page usage docs: update docs after introducing delaytop ...
2025-07-15blktrace: add zoned block commands to blk_fill_rwbsJohannes Thumshirn
Add zoned block commands to blk_fill_rwbs: - ZONE APPEND will be decoded as 'ZA' - ZONE RESET will be decoded as 'ZR' - ZONE RESET ALL will be decoded as 'ZRA' - ZONE FINISH will be decoded as 'ZF' - ZONE OPEN will be decoded as 'ZO' - ZONE CLOSE will be decoded as 'ZC' Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20250715115324.53308-2-johannes.thumshirn@wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-07-09blktrace: use rbuf->stats.full as a drop indicator in relayfsJason Xing
Replace internal subbuf_start in blktrace with the default policy in relayfs. Remove dropped field from struct blktrace. Correspondingly, call the common helper in relay. By incrementing full_count to keep track of how many times we encountered a full buffer issue, user space will know how many events were lost. Link: https://lkml.kernel.org/r/20250612061201.34272-5-kerneljasonxing@gmail.com Signed-off-by: Jason Xing <kernelxing@tencent.com> Reviewed-by: Yushan Zhou <katrinzhou@tencent.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-09relayfs: abolish prev_paddingJason Xing
Patch series "relayfs: misc changes", v5. The series mostly focuses on the error counters which helps every user debug their own kernel module. This patch (of 5): prev_padding represents the unused space of certain subbuffer. If the content of a call of relay_write() exceeds the limit of the remainder of this subbuffer, it will skip storing in the rest space and record the start point as buf->prev_padding in relay_switch_subbuf(). Since the buf is a per-cpu big buffer, the point of prev_padding as a global value for the whole buffer instead of a single subbuffer (whose padding info is stored in buf->padding[]) seems meaningless from the real use cases, so we don't bother to record it any more. Link: https://lkml.kernel.org/r/20250612061201.34272-1-kerneljasonxing@gmail.com Link: https://lkml.kernel.org/r/20250612061201.34272-2-kerneljasonxing@gmail.com Signed-off-by: Jason Xing <kernelxing@tencent.com> Reviewed-by: Yushan Zhou <katrinzhou@tencent.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-23traceevent/block: Add REQ_ATOMIC flag to block trace eventsRitesh Harjani (IBM)
Filesystems like XFS can implement atomic write I/O using either REQ_ATOMIC flag set in the bio or via CoW operation. It will be useful if we have a flag in trace events to distinguish between the two. This patch adds char 'U' (Untorn writes) to rwbs field of the trace events if REQ_ATOMIC flag is set in the bio. <W/ REQ_ATOMIC> ================= xfs_io-4238 [009] ..... 4148.126843: block_rq_issue: 259,0 WFSU 16384 () 768 + 32 none,0,0 [xfs_io] <idle>-0 [009] d.h1. 4148.129864: block_rq_complete: 259,0 WFSU () 768 + 32 none,0,0 [0] <W/O REQ_ATOMIC> =============== xfs_io-4237 [010] ..... 4143.325616: block_rq_issue: 259,0 WS 16384 () 768 + 32 none,0,0 [xfs_io] <idle>-0 [010] d.H1. 4143.329138: block_rq_complete: 259,0 WS () 768 + 32 none,0,0 [0] Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/44317cb2ec4588f6a2c1501a96684e6a1196e8ba.1747921498.git.ritesh.list@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-05block: remove bounce buffering supportChristoph Hellwig
The block layer bounce buffering support is unused now, remove it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20250505081138.3435992-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-12-23blktrace: remove redundant return at end of functionColin Ian King
A recent change added return 0 before an existing return statement at the end of function blk_trace_setup. The final return is now redundant, so remove it. Fixes: 64d124798244 ("blktrace: move copy_[to|from]_user() out of ->debugfs_lock") Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Link: https://lore.kernel.org/r/20241204150450.399005-1-colin.i.king@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-12-23blktrace: move copy_[to|from]_user() out of ->debugfs_lockMing Lei
Move copy_[to|from]_user() out of ->debugfs_lock and cut the dependency between mm->mmap_lock and q->debugfs_lock, then we avoids lots of lockdep false positive warning. Obviously ->debug_lock isn't needed for copy_[to|from]_user(). The only behavior change is to call blk_trace_remove() in case of setup failure handling by re-grabbing ->debugfs_lock, and this way is just fine since we do cover concurrent setup() & remove(). Reported-by: syzbot+91585b36b538053343e4@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-block/67450fd4.050a0220.1286eb.0007.GAE@google.com/ Closes: https://lore.kernel.org/linux-block/6742e584.050a0220.1cc393.0038.GAE@google.com/ Closes: https://lore.kernel.org/linux-block/6742a600.050a0220.1cc393.002e.GAE@google.com/ Closes: https://lore.kernel.org/linux-block/67420102.050a0220.1cc393.0019.GAE@google.com/ Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20241128125029.4152292-3-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-12-23blktrace: don't centralize grabbing q->debugfs_mutex in blk_trace_ioctlMing Lei
Call each handler directly and the handler do grab q->debugfs_mutex, prepare for killing dependency between ->debug_mutex and ->mmap_lock. Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20241128125029.4152292-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-25blktrace: convert strncpy() to strscpy_pad()Arnd Bergmann
gcc-9 warns about a possibly non-terminated string copy: kernel/trace/blktrace.c: In function 'do_blk_trace_setup': kernel/trace/blktrace.c:527:2: error: 'strncpy' specified bound 32 equals destination size [-Werror=stringop-truncation] Newer versions are fine here because they see the following explicit nul-termination. Using strscpy_pad() avoids the warning and simplifies the code a little. The padding helps give a clean buffer to userspace. Link: https://lkml.kernel.org/r/20240409140059.3806717-5-arnd@kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Justin Stitt <justinstitt@google.com> Cc: Alexey Starikovskiy <astarikovskiy@suse.de> Cc: Bob Moore <robert.moore@intel.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Len Brown <lenb@kernel.org> Cc: Lin Ming <ming.m.lin@intel.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nicolas Schier <nicolas@fjasle.eu> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: "Richard Russon (FlatCap)" <ldm@flatcap.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-02-21block: remove more NULL checks after bdev_get_queue()Juhyung Park
bdev_get_queue() never returns NULL. Several commits [1][2] have been made before to remove such superfluous checks, but some still remained. For places where bdev_get_queue() is called solely for NULL checks, it is removed entirely. [1] commit ec9fd2a13d74 ("blk-lib: don't check bdev_get_queue() NULL check") [2] commit fea127b36c93 ("block: remove superfluous check for request queue in bdev_is_zoned()") Signed-off-by: Juhyung Park <qkrwngud825@gmail.com> Reviewed-by: Pankaj Raghav <p.raghav@samsung.com> Link: https://lore.kernel.org/r/20230203024029.48260-1-qkrwngud825@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-06trace/blktrace: fix memory leak with using debugfs_lookup()Greg Kroah-Hartman
When calling debugfs_lookup() the result must have dput() called on it, otherwise the memory will leak over time. To make things simpler, just call debugfs_lookup_and_remove() instead which handles all of the logic at once. Cc: Jens Axboe <axboe@kernel.dk> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: linux-block@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-trace-kernel@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20230202141956.2299521-1-gregkh@linuxfoundation.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-08blktrace: Fix output non-blktrace event when blk_classic option enabledYang Jihong
When the blk_classic option is enabled, non-blktrace events must be filtered out. Otherwise, events of other types are output in the blktrace classic format, which is unexpected. The problem can be triggered in the following ways: # echo 1 > /sys/kernel/debug/tracing/options/blk_classic # echo 1 > /sys/kernel/debug/tracing/events/enable # echo blk > /sys/kernel/debug/tracing/current_tracer # cat /sys/kernel/debug/tracing/trace_pipe Fixes: c71a89615411 ("blktrace: add ftrace plugin") Signed-off-by: Yang Jihong <yangjihong1@huawei.com> Link: https://lore.kernel.org/r/20221122040410.85113-1-yangjihong1@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-01block: bdev & blktrace: use consistent function doc. notationRandy Dunlap
Use only one hyphen in kernel-doc notation between the function name and its short description. The is the documented kerenl-doc format. It also fixes the HTML presentation to be consistent with other functions. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Link: https://lore.kernel.org/r/20221201070331.25685-1-rdunlap@infradead.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-20blktrace: remove unnessary stop block trace in 'blk_trace_shutdown'Ye Bin
As previous commit, 'blk_trace_cleanup' will stop block trace if block trace's state is 'Blktrace_running'. So remove unnessary stop block trace in 'blk_trace_shutdown'. Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20221019033602.752383-4-yebin@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-20blktrace: fix possible memleak in '__blk_trace_remove'Ye Bin
When test as follows: step1: ioctl(sda, BLKTRACESETUP, &arg) step2: ioctl(sda, BLKTRACESTART, NULL) step3: ioctl(sda, BLKTRACETEARDOWN, NULL) step4: ioctl(sda, BLKTRACESETUP, &arg) Got issue as follows: debugfs: File 'dropped' in directory 'sda' already present! debugfs: File 'msg' in directory 'sda' already present! debugfs: File 'trace0' in directory 'sda' already present! And also find syzkaller report issue like "KASAN: use-after-free Read in relay_switch_subbuf" "https://syzkaller.appspot.com/bug?id=13849f0d9b1b818b087341691be6cc3ac6a6bfb7" If remove block trace without stop(BLKTRACESTOP) block trace, '__blk_trace_remove' will just set 'q->blk_trace' with NULL. However, debugfs file isn't removed, so will report file already present when call BLKTRACESETUP. static int __blk_trace_remove(struct request_queue *q) { struct blk_trace *bt; bt = rcu_replace_pointer(q->blk_trace, NULL, lockdep_is_held(&q->debugfs_mutex)); if (!bt) return -EINVAL; if (bt->trace_state != Blktrace_running) blk_trace_cleanup(q, bt); return 0; } If do test as follows: step1: ioctl(sda, BLKTRACESETUP, &arg) step2: ioctl(sda, BLKTRACESTART, NULL) step3: ioctl(sda, BLKTRACETEARDOWN, NULL) step4: remove sda There will remove debugfs directory which will remove recursively all file under directory. >> blk_release_queue >> debugfs_remove_recursive(q->debugfs_dir) So all files which created in 'do_blk_trace_setup' are removed, and 'dentry->d_inode' is NULL. But 'q->blk_trace' is still in 'running_trace_lock', 'trace_note_tsk' will traverse 'running_trace_lock' all nodes. >>trace_note_tsk >> trace_note >> relay_reserve >> relay_switch_subbuf >> d_inode(buf->dentry)->i_size To solve above issues, reference commit '5afedf670caf', call 'blk_trace_cleanup' unconditionally in '__blk_trace_remove' and first stop block trace in 'blk_trace_cleanup'. Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20221019033602.752383-3-yebin@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-20blktrace: introduce 'blk_trace_{start,stop}' helperYe Bin
Introduce 'blk_trace_{start,stop}' helper. No functional changed. Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20221019033602.752383-2-yebin@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-15blktrace: Fix the blk_fill_rwbs() kernel-doc headerBart Van Assche
Reflect recent changes in the blk_fill_rwbs() kernel-doc header. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Christoph Hellwig <hch@lst.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Chaitanya Kulkarni <kch@nvidia.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Fixes: 919dbca8670d ("blktrace: Use the new blk_opf_t type") Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20220715184735.2326034-3-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-14blktrace: Use the new blk_opf_t typeBart Van Assche
Improve static type checking by using the new blk_opf_t type for a function argument that represents a combination of a request operation and request flags. Rename that argument from 'op' into 'opf' to make its role more clear. Cc: Christoph Hellwig <hch@lst.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Chaitanya Kulkarni <kch@nvidia.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20220714180729.1065367-12-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-14blktrace: Trace remapped requests correctlyBart Van Assche
Trace the remapped operation and its flags instead of only the data direction of remapped operations. This issue was detected by analyzing the warnings reported by sparse related to the new blk_opf_t type. Reviewed-by: Jun'ichi Nomura <junichi.nomura@nec.com> Cc: Mike Snitzer <snitzer@kernel.org> Cc: Mike Christie <michael.christie@oracle.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Chaitanya Kulkarni <kch@nvidia.com> Fixes: 1b9a9ab78b0a ("blktrace: use op accessors") Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20220714180729.1065367-11-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>