792bb6eb86233 ("io_uring: don't take uring_lock during iowq cancel")
inadvertently fixed this issue in v5.12. This patch cherry-picks the
hunk of commit which does so.
Syzbot vomit (snipped):
==================================================================
BUG: KASAN: double-free or invalid-free in slab_free mm/slub.c:3195 [inline]
BUG: KASAN: double-free or invalid-free in kfree+0xca/0x310 mm/slub.c:4183
CPU: 1 PID: 431 Comm: syz-executor823 Not tainted 5.10.75-syzkaller-01082-g234d53d2bb60 #0
Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
print_address_description+0x8d/0x3d0 mm/kasan/report.c:233
kasan_report_invalid_free+0x58/0x130 mm/kasan/report.c:358
____kasan_slab_free+0x14b/0x170 mm/kasan/common.c:362
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:368
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:1596 [inline]
slab_free_freelist_hook+0xb2/0x180 mm/slub.c:1621
slab_free mm/slub.c:3195 [inline]
kfree+0xca/0x310 mm/slub.c:4183
__io_queue_deferred fs/io_uring.c:1541 [inline]
io_commit_cqring+0x76a/0xa00 fs/io_uring.c:1587
io_iopoll_complete fs/io_uring.c:2378 [inline]
io_do_iopoll+0x1e18/0x23f0 fs/io_uring.c:2431
io_iopoll_try_reap_events+0x116/0x290 fs/io_uring.c:2470
io_ring_ctx_wait_and_kill+0x295/0x670 fs/io_uring.c:8575
io_uring_release+0x5b/0x70 fs/io_uring.c:8602
__fput+0x348/0x7d0 fs/file_table.c:281
____fput+0x15/0x20 fs/file_table.c:314
task_work_run+0x147/0x1b0 kernel/task_work.c:154
exit_task_work include/linux/task_work.h:30 [inline]
do_exit+0x70e/0x23a0 kernel/exit.c:813
do_group_exit+0x16a/0x2d0 kernel/exit.c:910
__do_sys_exit_group+0x17/0x20 kernel/exit.c:921
__se_sys_exit_group+0x14/0x20 kernel/exit.c:919
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:919
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Cc: stable <stable@xxxxxxxxxxxxxxx> # 5.10.x
Reported-by: syzbot+59d8a1f4e60c20c066cf@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
---
fs/io_uring.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 26753d0cb4312..361f8ae96c36f 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2075,7 +2075,9 @@ static void io_req_task_cancel(struct callback_head *cb)
struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
struct io_ring_ctx *ctx = req->ctx;
+ mutex_lock(&ctx->uring_lock);
__io_req_task_cancel(req, -ECANCELED);
+ mutex_unlock(&ctx->uring_lock);
percpu_ref_put(&ctx->refs);
}
--
2.33.0.1079.g6e70778dc9-goog
