diff options
| author | Jens Axboe <axboe@kernel.dk> | 2026-02-11 15:12:03 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-02-11 15:20:44 -0700 |
| commit | a6bded921ed35f21b3f6bd8e629bf488499ca442 (patch) | |
| tree | 05ba59bedb64c1ccd9784802fb824fab4398f1de /io_uring | |
| parent | 0efc331d78b043b9d8477c64e279058062d36a0b (diff) | |
io_uring/filetable: clamp alloc_hint to the configured alloc range
Explicit fixed file install/remove operations on slots outside the
configured alloc range can corrupt alloc_hint via io_file_bitmap_set()
and io_file_bitmap_clear(), which unconditionally update alloc_hint to
the bit position. This causes subsequent auto-allocations to fall
outside the configured range.
For example, if the alloc range is [10, 20) and a file is removed at
slot 2, alloc_hint gets set to 2. The next auto-alloc then starts
searching from slot 2, potentially returning a slot below the range.
Fix this by clamping alloc_hint to [file_alloc_start, file_alloc_end)
at the top of io_file_bitmap_get() before starting the search.
Cc: stable@vger.kernel.org
Fixes: 6e73dffbb93c ("io_uring: let to set a range for file slot allocation")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/filetable.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/io_uring/filetable.c b/io_uring/filetable.c index 794ef95df293..cb1838c9fc37 100644 --- a/io_uring/filetable.c +++ b/io_uring/filetable.c @@ -22,6 +22,10 @@ static int io_file_bitmap_get(struct io_ring_ctx *ctx) if (!table->bitmap) return -ENFILE; + if (table->alloc_hint < ctx->file_alloc_start || + table->alloc_hint >= ctx->file_alloc_end) + table->alloc_hint = ctx->file_alloc_start; + do { ret = find_next_zero_bit(table->bitmap, nr, table->alloc_hint); if (ret != nr) |