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| author | Jens Axboe <axboe@kernel.dk> | 2023-10-02 19:51:38 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-10-03 08:12:54 -0600 |
| commit | 1658633c04653578429ff5dfc62fdc159203a8f2 (patch) | |
| tree | caab58969a6d936ba39f46c0432752c25ed59c33 /io_uring | |
| parent | f8024f1f36a30a082b0457d5779c8847cea57f57 (diff) | |
| download | lwn-1658633c04653578429ff5dfc62fdc159203a8f2.tar.gz lwn-1658633c04653578429ff5dfc62fdc159203a8f2.zip | |
io_uring: ensure io_lockdep_assert_cq_locked() handles disabled rings
io_lockdep_assert_cq_locked() checks that locking is correctly done when
a CQE is posted. If the ring is setup in a disabled state with
IORING_SETUP_R_DISABLED, then ctx->submitter_task isn't assigned until
the ring is later enabled. We generally don't post CQEs in this state,
as no SQEs can be submitted. However it is possible to generate a CQE
if tagged resources are being updated. If this happens and PROVE_LOCKING
is enabled, then the locking check helper will dereference
ctx->submitter_task, which hasn't been set yet.
Fixup io_lockdep_assert_cq_locked() to handle this case correctly. While
at it, convert it to a static inline as well, so that generated line
offsets will actually reflect which condition failed, rather than just
the line offset for io_lockdep_assert_cq_locked() itself.
Reported-and-tested-by: syzbot+efc45d4e7ba6ab4ef1eb@syzkaller.appspotmail.com
Fixes: f26cc9593581 ("io_uring: lockdep annotate CQ locking")
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.h | 41 |
1 files changed, 27 insertions, 14 deletions
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h index 547c30582fb8..0bc145614a6e 100644 --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -86,20 +86,33 @@ bool __io_alloc_req_refill(struct io_ring_ctx *ctx); bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task, bool cancel_all); -#define io_lockdep_assert_cq_locked(ctx) \ - do { \ - lockdep_assert(in_task()); \ - \ - if (ctx->flags & IORING_SETUP_IOPOLL) { \ - lockdep_assert_held(&ctx->uring_lock); \ - } else if (!ctx->task_complete) { \ - lockdep_assert_held(&ctx->completion_lock); \ - } else if (ctx->submitter_task->flags & PF_EXITING) { \ - lockdep_assert(current_work()); \ - } else { \ - lockdep_assert(current == ctx->submitter_task); \ - } \ - } while (0) +#if defined(CONFIG_PROVE_LOCKING) +static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx) +{ + lockdep_assert(in_task()); + + if (ctx->flags & IORING_SETUP_IOPOLL) { + lockdep_assert_held(&ctx->uring_lock); + } else if (!ctx->task_complete) { + lockdep_assert_held(&ctx->completion_lock); + } else if (ctx->submitter_task) { + /* + * ->submitter_task may be NULL and we can still post a CQE, + * if the ring has been setup with IORING_SETUP_R_DISABLED. + * Not from an SQE, as those cannot be submitted, but via + * updating tagged resources. + */ + if (ctx->submitter_task->flags & PF_EXITING) + lockdep_assert(current_work()); + else + lockdep_assert(current == ctx->submitter_task); + } +} +#else +static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx) +{ +} +#endif static inline void io_req_task_work_add(struct io_kiocb *req) { |