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| author |   Pavel Begunkov <asml.silence@gmail.com> | 2021-08-10 02:44:23 +0100 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2021-08-09 19:59:28 -0600 |
| commit | 43597aac1f87230cb565ab354d331682f13d3c7a (patch) | |
| tree | a5d8303429c786df465bfe988bac84e266d4900c /fs | |
| parent | io_uring: drop ctx->uring_lock before flushing work item (diff) | |
| download | linux-dev-43597aac1f87230cb565ab354d331682f13d3c7a.tar.xz linux-dev-43597aac1f87230cb565ab354d331682f13d3c7a.zip | |
io_uring: fix ctx-exit io_rsrc_put_work() deadlock
__io_rsrc_put_work() might need ->uring_lock, so nobody should wait for
rsrc nodes holding the mutex. However, that's exactly what
io_ring_ctx_free() does with io_wait_rsrc_data().
Split it into rsrc wait + dealloc, and move the first one out of the
lock.
Cc: stable@vger.kernel.org
Fixes: b60c8dce33895 ("io_uring: preparation for rsrc tagging")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0130c5c2693468173ec1afab714e0885d2c9c363.1628559783.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/io_uring.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 0c3e90f974e9..04c6d059ea94 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8652,13 +8652,10 @@ static void io_req_caches_free(struct io_ring_ctx *ctx) mutex_unlock(&ctx->uring_lock); } -static bool io_wait_rsrc_data(struct io_rsrc_data *data) +static void io_wait_rsrc_data(struct io_rsrc_data *data) { - if (!data) - return false; - if (!atomic_dec_and_test(&data->refs)) + if (data && !atomic_dec_and_test(&data->refs)) wait_for_completion(&data->done); - return true; } static void io_ring_ctx_free(struct io_ring_ctx *ctx) @@ -8670,10 +8667,14 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx) ctx->mm_account = NULL; } + /* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */ + io_wait_rsrc_data(ctx->buf_data); + io_wait_rsrc_data(ctx->file_data); + mutex_lock(&ctx->uring_lock); - if (io_wait_rsrc_data(ctx->buf_data)) + if (ctx->buf_data) __io_sqe_buffers_unregister(ctx); - if (io_wait_rsrc_data(ctx->file_data)) + if (ctx->file_data) __io_sqe_files_unregister(ctx); if (ctx->rings) __io_cqring_overflow_flush(ctx, true); |