The patch titled Subject: proc: proc_maps_open allow proc_mem_open to return NULL has been added to the -mm mm-hotfixes-unstable branch. Its filename is proc-proc_maps_open-allow-proc_mem_open-to-return-null.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Jialin Wang wjl.linux@gmail.com Subject: proc: proc_maps_open allow proc_mem_open to return NULL Date: Fri, 8 Aug 2025 00:54:55 +0800

commit 65c66047259f ("proc: fix the issue of proc_mem_open returning NULL") breaks `perf record -g -p PID` when profiling a kernel thread.

The strace of `perf record -g -p $(pgrep kswapd0)` shows:

openat(AT_FDCWD, "/proc/65/task/65/maps", O_RDONLY) = -1 ESRCH (No such process)

This patch partially reverts the commit to fix it.

Link: https://lkml.kernel.org/r/20250807165455.73656-1-wjl.linux@gmail.com Fixes: 65c66047259f ("proc: fix the issue of proc_mem_open returning NULL") Signed-off-by: Jialin Wang wjl.linux@gmail.com Cc: Penglei Jiang superman.xpt@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/proc/task_mmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/proc/task_mmu.c~proc-proc_maps_open-allow-proc_mem_open-to-return-null +++ a/fs/proc/task_mmu.c @@ -340,8 +340,8 @@ static int proc_maps_open(struct inode *

priv->inode = inode; priv->mm = proc_mem_open(inode, PTRACE_MODE_READ); - if (IS_ERR_OR_NULL(priv->mm)) { - int err = priv->mm ? PTR_ERR(priv->mm) : -ESRCH; + if (IS_ERR(priv->mm)) { + int err = PTR_ERR(priv->mm);

seq_release_private(inode, file); return err; _

Patches currently in -mm which might be from wjl.linux@gmail.com are

proc-proc_maps_open-allow-proc_mem_open-to-return-null.patch