This is a note to let you know that I've just added the patch titled
fs: sysfs_emit_at: Remove PAGE_SIZE alignment check
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-sysfs_emit_at-remove-page_size-alignment-check.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ebiggers@xxxxxxxxxx Fri Mar 17 13:57:17 2023
From: Eric Biggers <ebiggers@xxxxxxxxxx>
Date: Thu, 16 Mar 2023 23:27:43 -0700
Subject: fs: sysfs_emit_at: Remove PAGE_SIZE alignment check
To: stable@xxxxxxxxxxxxxxx
Cc: Joe Perches <joe@xxxxxxxxxxx>, Lucas Wei <lucaswei@xxxxxxxxxx>, linux-mm@xxxxxxxxx, kernel test robot <yujie.liu@xxxxxxxxx>
Message-ID: <20230317062743.313169-1-ebiggers@xxxxxxxxxx>
From: Eric Biggers <ebiggers@xxxxxxxxxx>
From: Eric Biggers <ebiggers@xxxxxxxxxx>
[No upstream commit because this fixes a bug in a backport.]
Before upstream commit 59bb47985c1d ("mm, sl[aou]b: guarantee natural
alignment for kmalloc(power-of-two)") which went into v5.4, kmalloc did
*not* always guarantee that PAGE_SIZE allocations are PAGE_SIZE-aligned.
Upstream commit 2efc459d06f1 ("sysfs: Add sysfs_emit and sysfs_emit_at
to format sysfs output") added two WARN()s that trigger when PAGE_SIZE
allocations are not PAGE_SIZE-aligned. This was backported to old
kernels that don't guarantee PAGE_SIZE alignment.
Commit 10ddfb495232 ("fs: sysfs_emit: Remove PAGE_SIZE alignment check")
in 4.19.y, and its equivalent in 4.14.y and 4.9.y, tried to fix this
bug. However, only it handled sysfs_emit(), not sysfs_emit_at().
Fix it in sysfs_emit_at() too.
A reproducer is to build the kernel with the following options:
CONFIG_SLUB=y
CONFIG_SLUB_DEBUG=y
CONFIG_SLUB_DEBUG_ON=y
CONFIG_PM=y
CONFIG_SUSPEND=y
CONFIG_PM_WAKELOCKS=y
Then run:
echo foo > /sys/power/wake_lock && cat /sys/power/wake_lock
Fixes: cb1f69d53ac8 ("sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output")
Reported-by: kernel test robot <yujie.liu@xxxxxxxxx>
Link: https://lore.kernel.org/r/202303141634.1e64fd76-yujie.liu@xxxxxxxxx
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/sysfs/file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -599,7 +599,7 @@ int sysfs_emit_at(char *buf, int at, con
va_list args;
int len;
- if (WARN(!buf || offset_in_page(buf) || at < 0 || at >= PAGE_SIZE,
+ if (WARN(!buf || at < 0 || at >= PAGE_SIZE,
"invalid sysfs_emit_at: buf:%p at:%d\n", buf, at))
return 0;
Patches currently in stable-queue which might be from ebiggers@xxxxxxxxxx are
queue-4.19/fs-sysfs_emit_at-remove-page_size-alignment-check.patch
queue-4.19/ext4-fix-cgroup-writeback-accounting-with-fs-layer-encryption.patch
