[ upstream commit 3181e22fb79910c7071e84a43af93ac89e8a7106 ]
There are reports of mariadb hangs, which is caused by a missing barrier in the waking code resulting in waiters losing events.
The problem was introduced in a backport 3ab9326f93ec4 ("io_uring: wake up optimisations"), and the change restores the barrier present in the original commit 3ab9326f93ec4 ("io_uring: wake up optimisations")
Reported by: Xan Charbonnet xan@charbonnet.com Fixes: 3ab9326f93ec4 ("io_uring: wake up optimisations") Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1093243#99 Signed-off-by: Pavel Begunkov asml.silence@gmail.com --- io_uring/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 9b58ba4616d40..e5a8ee944ef59 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -592,8 +592,10 @@ static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx) io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_commit_cqring_flush(ctx); - if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) + if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) { + smp_mb(); __io_cqring_wake(ctx); + } }
void io_cq_unlock_post(struct io_ring_ctx *ctx)
On 1/24/25 11:53 AM, Pavel Begunkov wrote:
[ upstream commit 3181e22fb79910c7071e84a43af93ac89e8a7106 ]
There are reports of mariadb hangs, which is caused by a missing barrier in the waking code resulting in waiters losing events.
The problem was introduced in a backport 3ab9326f93ec4 ("io_uring: wake up optimisations"), and the change restores the barrier present in the original commit 3ab9326f93ec4 ("io_uring: wake up optimisations")
Reported by: Xan Charbonnet xan@charbonnet.com Fixes: 3ab9326f93ec4 ("io_uring: wake up optimisations") Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1093243#99 Signed-off-by: Pavel Begunkov asml.silence@gmail.com
io_uring/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 9b58ba4616d40..e5a8ee944ef59 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -592,8 +592,10 @@ static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx) io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_commit_cqring_flush(ctx);
- if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
- if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) {
smp_mb();- }
}
We could probably just s/__io_cqring_wake/io_cqring_wake here to get the same effect. Not that it really matters, it's just simpler.
On 1/24/25 20:47, Jens Axboe wrote:
On 1/24/25 11:53 AM, Pavel Begunkov wrote:
[ upstream commit 3181e22fb79910c7071e84a43af93ac89e8a7106 ]
There are reports of mariadb hangs, which is caused by a missing barrier in the waking code resulting in waiters losing events.
The problem was introduced in a backport 3ab9326f93ec4 ("io_uring: wake up optimisations"), and the change restores the barrier present in the original commit 3ab9326f93ec4 ("io_uring: wake up optimisations")
Reported by: Xan Charbonnet xan@charbonnet.com Fixes: 3ab9326f93ec4 ("io_uring: wake up optimisations") Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1093243#99 Signed-off-by: Pavel Begunkov asml.silence@gmail.com
io_uring/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 9b58ba4616d40..e5a8ee944ef59 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -592,8 +592,10 @@ static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx) io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_commit_cqring_flush(ctx);
- if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
- if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) {
smp_mb();- } }
We could probably just s/__io_cqring_wake/io_cqring_wake here to get the same effect. Not that it really matters, it's just simpler.
Right, I noticed but am keeping it closer to the original in case we'd need to port more in the future.
On 1/24/25 2:23 PM, Pavel Begunkov wrote:
On 1/24/25 20:47, Jens Axboe wrote:
On 1/24/25 11:53 AM, Pavel Begunkov wrote:
[ upstream commit 3181e22fb79910c7071e84a43af93ac89e8a7106 ]
There are reports of mariadb hangs, which is caused by a missing barrier in the waking code resulting in waiters losing events.
The problem was introduced in a backport 3ab9326f93ec4 ("io_uring: wake up optimisations"), and the change restores the barrier present in the original commit 3ab9326f93ec4 ("io_uring: wake up optimisations")
Reported by: Xan Charbonnet xan@charbonnet.com Fixes: 3ab9326f93ec4 ("io_uring: wake up optimisations") Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1093243#99 Signed-off-by: Pavel Begunkov asml.silence@gmail.com
io_uring/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 9b58ba4616d40..e5a8ee944ef59 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -592,8 +592,10 @@ static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx) io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_commit_cqring_flush(ctx); - if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) + if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) { + smp_mb(); __io_cqring_wake(ctx); + } }
We could probably just s/__io_cqring_wake/io_cqring_wake here to get the same effect. Not that it really matters, it's just simpler.
Right, I noticed but am keeping it closer to the original in case we'd need to port more in the future.
Yep that's fine, let's just go with this one as-is.
-----Original Message----- From: Pavel Begunkov asml.silence@gmail.com Sent: Saturday, January 25, 2025 2:54 AM To: io-uring@vger.kernel.org; stable@vger.kernel.org Cc: asml.silence@gmail.com; Xan Charbonnet xan@charbonnet.com; Salvatore Bonaccorso carnil@debian.org Subject: [PATCH stable-6.1 1/1] io_uring: fix waiters missing wake ups
[ upstream commit 3181e22fb79910c7071e84a43af93ac89e8a7106 ]
There are reports of mariadb hangs, which is caused by a missing barrier in the waking code resulting in waiters losing events.
The problem was introduced in a backport 3ab9326f93ec4 ("io_uring: wake up optimisations"), and the change restores the barrier present in the original commit 3ab9326f93ec4 ("io_uring: wake up optimisations")
Reported by: Xan Charbonnet xan@charbonnet.com Fixes: 3ab9326f93ec4 ("io_uring: wake up optimisations") Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1093243#99 Signed-off-by: Pavel Begunkov asml.silence@gmail.com
io_uring/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 9b58ba4616d40..e5a8ee944ef59 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -592,8 +592,10 @@ static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx) io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_commit_cqring_flush(ctx);
- if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
- if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) {
smp_mb();- }
}
void io_cq_unlock_post(struct io_ring_ctx *ctx)
2.47.1
Reviewed-by: Li Zetao lizetao1@huawei.com
-- Li Zetao
On Sat, Jan 25, 2025 at 06:59:06AM +0000, lizetao wrote:
-----Original Message----- From: Pavel Begunkov asml.silence@gmail.com Sent: Saturday, January 25, 2025 2:54 AM To: io-uring@vger.kernel.org; stable@vger.kernel.org Cc: asml.silence@gmail.com; Xan Charbonnet xan@charbonnet.com; Salvatore Bonaccorso carnil@debian.org Subject: [PATCH stable-6.1 1/1] io_uring: fix waiters missing wake ups
[ upstream commit 3181e22fb79910c7071e84a43af93ac89e8a7106 ]
There are reports of mariadb hangs, which is caused by a missing barrier in the waking code resulting in waiters losing events.
The problem was introduced in a backport 3ab9326f93ec4 ("io_uring: wake up optimisations"), and the change restores the barrier present in the original commit 3ab9326f93ec4 ("io_uring: wake up optimisations")
Reported by: Xan Charbonnet xan@charbonnet.com Fixes: 3ab9326f93ec4 ("io_uring: wake up optimisations") Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1093243#99 Signed-off-by: Pavel Begunkov asml.silence@gmail.com
io_uring/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 9b58ba4616d40..e5a8ee944ef59 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -592,8 +592,10 @@ static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx) io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_commit_cqring_flush(ctx);
- if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
- if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) {
smp_mb();- }
}
void io_cq_unlock_post(struct io_ring_ctx *ctx)
2.47.1
Reviewed-by: Li Zetao lizetao1@huawei.com
Now queued up, thanks.
greg k-h
[ Sasha's backport helper bot ]
Hi,
No upstream commit was identified. Using temporary commit for testing.
Results of testing on various branches:
| Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-6.1.y | Success | Success |
linux-stable-mirror@lists.linaro.org
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