The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 26e5c67deb2e1f42a951f022fdf5b9f7eb747b01
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101628-exclude-hamstring-8d43@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 26e5c67deb2e1f42a951f022fdf5b9f7eb747b01 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong(a)kernel.org>
Date: Mon, 15 Sep 2025 17:24:17 -0700
Subject: [PATCH] fuse: fix livelock in synchronous file put from fuseblk
workers
I observed a hang when running generic/323 against a fuseblk server.
This test opens a file, initiates a lot of AIO writes to that file
descriptor, and closes the file descriptor before the writes complete.
Unsurprisingly, the AIO exerciser threads are mostly stuck waiting for
responses from the fuseblk server:
# cat /proc/372265/task/372313/stack
[<0>] request_wait_answer+0x1fe/0x2a0 [fuse]
[<0>] __fuse_simple_request+0xd3/0x2b0 [fuse]
[<0>] fuse_do_getattr+0xfc/0x1f0 [fuse]
[<0>] fuse_file_read_iter+0xbe/0x1c0 [fuse]
[<0>] aio_read+0x130/0x1e0
[<0>] io_submit_one+0x542/0x860
[<0>] __x64_sys_io_submit+0x98/0x1a0
[<0>] do_syscall_64+0x37/0xf0
[<0>] entry_SYSCALL_64_after_hwframe+0x4b/0x53
But the /weird/ part is that the fuseblk server threads are waiting for
responses from itself:
# cat /proc/372210/task/372232/stack
[<0>] request_wait_answer+0x1fe/0x2a0 [fuse]
[<0>] __fuse_simple_request+0xd3/0x2b0 [fuse]
[<0>] fuse_file_put+0x9a/0xd0 [fuse]
[<0>] fuse_release+0x36/0x50 [fuse]
[<0>] __fput+0xec/0x2b0
[<0>] task_work_run+0x55/0x90
[<0>] syscall_exit_to_user_mode+0xe9/0x100
[<0>] do_syscall_64+0x43/0xf0
[<0>] entry_SYSCALL_64_after_hwframe+0x4b/0x53
The fuseblk server is fuse2fs so there's nothing all that exciting in
the server itself. So why is the fuse server calling fuse_file_put?
The commit message for the fstest sheds some light on that:
"By closing the file descriptor before calling io_destroy, you pretty
much guarantee that the last put on the ioctx will be done in interrupt
context (during I/O completion).
Aha. AIO fgets a new struct file from the fd when it queues the ioctx.
The completion of the FUSE_WRITE command from userspace causes the fuse
server to call the AIO completion function. The completion puts the
struct file, queuing a delayed fput to the fuse server task. When the
fuse server task returns to userspace, it has to run the delayed fput,
which in the case of a fuseblk server, it does synchronously.
Sending the FUSE_RELEASE command sychronously from fuse server threads
is a bad idea because a client program can initiate enough simultaneous
AIOs such that all the fuse server threads end up in delayed_fput, and
now there aren't any threads left to handle the queued fuse commands.
Fix this by only using asynchronous fputs when closing files, and leave
a comment explaining why.
Cc: stable(a)vger.kernel.org # v2.6.38
Fixes: 5a18ec176c934c ("fuse: fix hang of single threaded fuseblk filesystem")
Signed-off-by: Darrick J. Wong <djwong(a)kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi(a)redhat.com>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 54786f62a9d8..f1ef77a0be05 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -356,8 +356,14 @@ void fuse_file_release(struct inode *inode, struct fuse_file *ff,
* Make the release synchronous if this is a fuseblk mount,
* synchronous RELEASE is allowed (and desirable) in this case
* because the server can be trusted not to screw up.
+ *
+ * Always use the asynchronous file put because the current thread
+ * might be the fuse server. This can happen if a process starts some
+ * aio and closes the fd before the aio completes. Since aio takes its
+ * own ref to the file, the IO completion has to drop the ref, which is
+ * how the fuse server can end up closing its clients' files.
*/
- fuse_file_put(ff, ff->fm->fc->destroy);
+ fuse_file_put(ff, false);
}
void fuse_release_common(struct file *file, bool isdir)
Two backports linked to build issues with GCC 15 have failed in this
version:
- ee2ab467bddf ("x86/boot: Use '-std=gnu11' to fix build with GCC 15")
- 8ba14d9f490a ("efi: libstub: Use '-std=gnu11' to fix build with GCC 15")
Conflicts have been solved, and described.
After that, this kernel version still didn't build with GCC 15:
In file included from include/uapi/linux/posix_types.h:5,
from include/uapi/linux/types.h:14,
from include/linux/types.h:6,
from arch/x86/realmode/rm/wakeup.h:11,
from arch/x86/realmode/rm/wakemain.c:2:
include/linux/stddef.h:11:9: error: cannot use keyword 'false' as enumeration constant
11 | false = 0,
| ^~~~~
include/linux/stddef.h:11:9: note: 'false' is a keyword with '-std=c23' onwards
include/linux/types.h:30:33: error: 'bool' cannot be defined via 'typedef'
30 | typedef _Bool bool;
| ^~~~
include/linux/types.h:30:33: note: 'bool' is a keyword with '-std=c23' onwards
include/linux/types.h:30:1: warning: useless type name in empty declaration
30 | typedef _Bool bool;
| ^~~~~~~
I initially fixed this by adding -std=gnu11 in arch/x86/Makefile, then I
realised this fix was already done in an upstream commit, created before
the GCC 15 release and not mentioning the error I had. This is patch 3.
When I was investigating my error, I noticed other commits were already
backported to stable versions. They were all adding -std=gnu11 in
different Makefiles. In their commit message, they were mentioning
'gnu11' was picked to use the same as the one from the main Makefile.
But this is not the case in this kernel version. Patch 4 fixes that.
Finally, I noticed extra warnings I didn't have in v5.10. Patch 5 fixes
that.
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
---
Alexey Dobriyan (1):
x86/boot: Compile boot code with -std=gnu11 too
Matthieu Baerts (NGI0) (1):
arch: back to -std=gnu89 in < v5.18
Nathan Chancellor (3):
x86/boot: Use '-std=gnu11' to fix build with GCC 15
efi: libstub: Use '-std=gnu11' to fix build with GCC 15
kernel/profile.c: use cpumask_available to check for NULL cpumask
arch/parisc/boot/compressed/Makefile | 2 +-
arch/s390/Makefile | 2 +-
arch/s390/purgatory/Makefile | 2 +-
arch/x86/Makefile | 2 +-
arch/x86/boot/compressed/Makefile | 1 +
drivers/firmware/efi/libstub/Makefile | 2 +-
kernel/profile.c | 6 +++---
7 files changed, 9 insertions(+), 8 deletions(-)
---
base-commit: cda7d335d88aa30485536aee3027540f41bf4f10
change-id: 20251017-v5-4-gcc-15-2d2ccb30432c
Best regards,
--
Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x cd32a0c0dcdf634f2e0e71f41c272e19dece6264
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101603-baggage-humming-330b@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From cd32a0c0dcdf634f2e0e71f41c272e19dece6264 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong(a)kernel.org>
Date: Tue, 8 Apr 2025 16:14:32 -0700
Subject: [PATCH] xfs: use deferred intent items for reaping crosslinked blocks
When we're removing rmap records for crosslinked blocks, use deferred
intent items so that we can try to free/unmap as many of the old data
structure's blocks as we can in the same transaction as the commit.
Cc: <stable(a)vger.kernel.org> # v6.6
Fixes: 1c7ce115e52106 ("xfs: reap large AG metadata extents when possible")
Signed-off-by: "Darrick J. Wong" <djwong(a)kernel.org>
Reviewed-by: Christoph Hellwig <hch(a)lst.de>
diff --git a/fs/xfs/scrub/reap.c b/fs/xfs/scrub/reap.c
index 8703897c0a9c..86d3d104b8d9 100644
--- a/fs/xfs/scrub/reap.c
+++ b/fs/xfs/scrub/reap.c
@@ -416,8 +416,6 @@ xreap_agextent_iter(
trace_xreap_dispose_unmap_extent(pag_group(sc->sa.pag), agbno,
*aglenp);
- rs->force_roll = true;
-
if (rs->oinfo == &XFS_RMAP_OINFO_COW) {
/*
* If we're unmapping CoW staging extents, remove the
@@ -426,11 +424,14 @@ xreap_agextent_iter(
*/
xfs_refcount_free_cow_extent(sc->tp, false, fsbno,
*aglenp);
+ rs->force_roll = true;
return 0;
}
- return xfs_rmap_free(sc->tp, sc->sa.agf_bp, sc->sa.pag, agbno,
- *aglenp, rs->oinfo);
+ xfs_rmap_free_extent(sc->tp, false, fsbno, *aglenp,
+ rs->oinfo->oi_owner);
+ rs->deferred++;
+ return 0;
}
trace_xreap_dispose_free_extent(pag_group(sc->sa.pag), agbno, *aglenp);
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101651-kerosene-quartered-684e@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b Mon Sep 17 00:00:00 2001
From: Xiao Liang <shaw.leon(a)gmail.com>
Date: Sun, 17 Aug 2025 00:30:15 +0800
Subject: [PATCH] padata: Reset next CPU when reorder sequence wraps around
When seq_nr wraps around, the next reorder job with seq 0 is hashed to
the first CPU in padata_do_serial(). Correspondingly, need reset pd->cpu
to the first one when pd->processed wraps around. Otherwise, if the
number of used CPUs is not a power of 2, padata_find_next() will be
checking a wrong list, hence deadlock.
Fixes: 6fc4dbcf0276 ("padata: Replace delayed timer with immediate workqueue in padata_reorder")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Xiao Liang <shaw.leon(a)gmail.com>
Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au>
diff --git a/kernel/padata.c b/kernel/padata.c
index f85f8bd788d0..833740d75483 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -291,8 +291,12 @@ static void padata_reorder(struct padata_priv *padata)
struct padata_serial_queue *squeue;
int cb_cpu;
- cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
processed++;
+ /* When sequence wraps around, reset to the first CPU. */
+ if (unlikely(processed == 0))
+ cpu = cpumask_first(pd->cpumask.pcpu);
+ else
+ cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
cb_cpu = padata->cb_cpu;
squeue = per_cpu_ptr(pd->squeue, cb_cpu);
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101651-sizing-subfloor-8c1d@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b Mon Sep 17 00:00:00 2001
From: Xiao Liang <shaw.leon(a)gmail.com>
Date: Sun, 17 Aug 2025 00:30:15 +0800
Subject: [PATCH] padata: Reset next CPU when reorder sequence wraps around
When seq_nr wraps around, the next reorder job with seq 0 is hashed to
the first CPU in padata_do_serial(). Correspondingly, need reset pd->cpu
to the first one when pd->processed wraps around. Otherwise, if the
number of used CPUs is not a power of 2, padata_find_next() will be
checking a wrong list, hence deadlock.
Fixes: 6fc4dbcf0276 ("padata: Replace delayed timer with immediate workqueue in padata_reorder")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Xiao Liang <shaw.leon(a)gmail.com>
Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au>
diff --git a/kernel/padata.c b/kernel/padata.c
index f85f8bd788d0..833740d75483 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -291,8 +291,12 @@ static void padata_reorder(struct padata_priv *padata)
struct padata_serial_queue *squeue;
int cb_cpu;
- cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
processed++;
+ /* When sequence wraps around, reset to the first CPU. */
+ if (unlikely(processed == 0))
+ cpu = cpumask_first(pd->cpumask.pcpu);
+ else
+ cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
cb_cpu = padata->cb_cpu;
squeue = per_cpu_ptr(pd->squeue, cb_cpu);
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101651-unlimited-rippling-daa6@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b Mon Sep 17 00:00:00 2001
From: Xiao Liang <shaw.leon(a)gmail.com>
Date: Sun, 17 Aug 2025 00:30:15 +0800
Subject: [PATCH] padata: Reset next CPU when reorder sequence wraps around
When seq_nr wraps around, the next reorder job with seq 0 is hashed to
the first CPU in padata_do_serial(). Correspondingly, need reset pd->cpu
to the first one when pd->processed wraps around. Otherwise, if the
number of used CPUs is not a power of 2, padata_find_next() will be
checking a wrong list, hence deadlock.
Fixes: 6fc4dbcf0276 ("padata: Replace delayed timer with immediate workqueue in padata_reorder")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Xiao Liang <shaw.leon(a)gmail.com>
Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au>
diff --git a/kernel/padata.c b/kernel/padata.c
index f85f8bd788d0..833740d75483 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -291,8 +291,12 @@ static void padata_reorder(struct padata_priv *padata)
struct padata_serial_queue *squeue;
int cb_cpu;
- cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
processed++;
+ /* When sequence wraps around, reset to the first CPU. */
+ if (unlikely(processed == 0))
+ cpu = cpumask_first(pd->cpumask.pcpu);
+ else
+ cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
cb_cpu = padata->cb_cpu;
squeue = per_cpu_ptr(pd->squeue, cb_cpu);
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101650-dreamless-dry-49d5@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b Mon Sep 17 00:00:00 2001
From: Xiao Liang <shaw.leon(a)gmail.com>
Date: Sun, 17 Aug 2025 00:30:15 +0800
Subject: [PATCH] padata: Reset next CPU when reorder sequence wraps around
When seq_nr wraps around, the next reorder job with seq 0 is hashed to
the first CPU in padata_do_serial(). Correspondingly, need reset pd->cpu
to the first one when pd->processed wraps around. Otherwise, if the
number of used CPUs is not a power of 2, padata_find_next() will be
checking a wrong list, hence deadlock.
Fixes: 6fc4dbcf0276 ("padata: Replace delayed timer with immediate workqueue in padata_reorder")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Xiao Liang <shaw.leon(a)gmail.com>
Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au>
diff --git a/kernel/padata.c b/kernel/padata.c
index f85f8bd788d0..833740d75483 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -291,8 +291,12 @@ static void padata_reorder(struct padata_priv *padata)
struct padata_serial_queue *squeue;
int cb_cpu;
- cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
processed++;
+ /* When sequence wraps around, reset to the first CPU. */
+ if (unlikely(processed == 0))
+ cpu = cpumask_first(pd->cpumask.pcpu);
+ else
+ cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
cb_cpu = padata->cb_cpu;
squeue = per_cpu_ptr(pd->squeue, cb_cpu);
The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101650-feline-ellipse-6256@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b Mon Sep 17 00:00:00 2001
From: Xiao Liang <shaw.leon(a)gmail.com>
Date: Sun, 17 Aug 2025 00:30:15 +0800
Subject: [PATCH] padata: Reset next CPU when reorder sequence wraps around
When seq_nr wraps around, the next reorder job with seq 0 is hashed to
the first CPU in padata_do_serial(). Correspondingly, need reset pd->cpu
to the first one when pd->processed wraps around. Otherwise, if the
number of used CPUs is not a power of 2, padata_find_next() will be
checking a wrong list, hence deadlock.
Fixes: 6fc4dbcf0276 ("padata: Replace delayed timer with immediate workqueue in padata_reorder")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Xiao Liang <shaw.leon(a)gmail.com>
Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au>
diff --git a/kernel/padata.c b/kernel/padata.c
index f85f8bd788d0..833740d75483 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -291,8 +291,12 @@ static void padata_reorder(struct padata_priv *padata)
struct padata_serial_queue *squeue;
int cb_cpu;
- cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
processed++;
+ /* When sequence wraps around, reset to the first CPU. */
+ if (unlikely(processed == 0))
+ cpu = cpumask_first(pd->cpumask.pcpu);
+ else
+ cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
cb_cpu = padata->cb_cpu;
squeue = per_cpu_ptr(pd->squeue, cb_cpu);
The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101649-sector-ruined-1f7a@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 501302d5cee0d8e8ec2c4a5919c37e0df9abc99b Mon Sep 17 00:00:00 2001
From: Xiao Liang <shaw.leon(a)gmail.com>
Date: Sun, 17 Aug 2025 00:30:15 +0800
Subject: [PATCH] padata: Reset next CPU when reorder sequence wraps around
When seq_nr wraps around, the next reorder job with seq 0 is hashed to
the first CPU in padata_do_serial(). Correspondingly, need reset pd->cpu
to the first one when pd->processed wraps around. Otherwise, if the
number of used CPUs is not a power of 2, padata_find_next() will be
checking a wrong list, hence deadlock.
Fixes: 6fc4dbcf0276 ("padata: Replace delayed timer with immediate workqueue in padata_reorder")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Xiao Liang <shaw.leon(a)gmail.com>
Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au>
diff --git a/kernel/padata.c b/kernel/padata.c
index f85f8bd788d0..833740d75483 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -291,8 +291,12 @@ static void padata_reorder(struct padata_priv *padata)
struct padata_serial_queue *squeue;
int cb_cpu;
- cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
processed++;
+ /* When sequence wraps around, reset to the first CPU. */
+ if (unlikely(processed == 0))
+ cpu = cpumask_first(pd->cpumask.pcpu);
+ else
+ cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu);
cb_cpu = padata->cb_cpu;
squeue = per_cpu_ptr(pd->squeue, cb_cpu);