+ proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix.patch added to -mm tree

+ proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix.patch added to -mm tree

[akpm]

The patch titled
     Subject: proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix
has been added to the -mm tree.  Its filename is
     proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix.patch

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------------------------------------------------------
From: Andrew Morton <akpm@linux-foundation.org>
Subject: proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix

further simplification

Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/proc/base.c |    9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

--- a/fs/proc/base.c~proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix
+++ a/fs/proc/base.c
@@ -384,15 +384,8 @@ static const struct file_operations proc
 static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 			  struct pid *pid, struct task_struct *task)
 {
-	unsigned long wchan;
-
 	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
-		wchan = get_wchan(task);
-	else
-		wchan = 0;
-
-	if (wchan)
-		seq_printf(m, "%ps", (void *) wchan);
+		seq_printf(m, "%ps", (void *)get_wchan(task));
 	else
 		seq_putc(m, '0');
 
_

Patches currently in -mm which might be from akpm@linux-foundation.org are

mm-add-prototype-for-__add_to_page_cache_locked-fix.patch
mm.patch
mm-fix-initialization-of-struct-page-for-holes-in-memory-layout-checkpatch-fixes.patch
mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings-fix-2.patch
kfence-kasan-make-kfence-compatible-with-kasan-fix.patch
proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix.patch
linux-next-rejects.patch
kmap-stupid-hacks-to-make-it-compile.patch
set_memory-allow-set_direct_map__noflush-for-multiple-pages-fix.patch
arch-mm-wire-up-memfd_secret-system-call-were-relevant-fix.patch
kernel-forkc-export-kernel_thread-to-modules.patch

Re: + proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix.patch added to -mm tree

[Alexey Dobriyan]

On Tue, Dec 22, 2020 at 06:18:34PM -0800, akpm@linux-foundation.org wrote:
>
>      proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix.patch

> --- a/fs/proc/base.c~proc-wchan-use-printk-format-instead-of-lookup_symbol_name-fix
> +++ a/fs/proc/base.c
> @@ -384,15 +384,8 @@ static const struct file_operations proc
>  static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
>  			  struct pid *pid, struct task_struct *task)
>  {
> -	unsigned long wchan;
> -
>  	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
> -		wchan = get_wchan(task);
> -	else
> -		wchan = 0;
> -
> -	if (wchan)
> -		seq_printf(m, "%ps", (void *) wchan);
> +		seq_printf(m, "%ps", (void *)get_wchan(task));
>  	else
>  		seq_putc(m, '0');

These patches change '0' to '0x0'.

Also /proc/*/wchan shows '0' for everything which is strange.

I'm not sure if we should care as wchan is obsoleted by /proc/*/stack .