2008-02-11 11:33:24

by Alexey Dobriyan

[permalink] [raw]
Subject: [PATCH] proc: print more information when removing non-empty directories

This usually saves one recompile to insert similar printk like below. :)

Sample nastygram:

remove_proc_entry: removing non-empty directory '/proc/foo', leaking at least 'bar'
------------[ cut here ]------------
WARNING: at fs/proc/generic.c:776 remove_proc_entry+0x18a/0x200()
Modules linked in: foo(-) container fan battery dock sbs ac sbshc backlight ipv6 loop af_packet amd_rng sr_mod i2c_amd8111 i2c_amd756 cdrom i2c_core button thermal processor
Pid: 3034, comm: rmmod Tainted: G M 2.6.25-rc1 #5

Call Trace:
[<ffffffff80231974>] warn_on_slowpath+0x64/0x90
[<ffffffff80232a6e>] printk+0x4e/0x60
[<ffffffff802d6c8a>] remove_proc_entry+0x18a/0x200
[<ffffffff8045cd88>] mutex_lock_nested+0x1c8/0x2d0
[<ffffffff8025f0f0>] __try_stop_module+0x0/0x40
[<ffffffff8025effd>] sys_delete_module+0x14d/0x200
[<ffffffff8045df3d>] lockdep_sys_exit_thunk+0x35/0x67
[<ffffffff8031c307>] __up_read+0x27/0xa0
[<ffffffff8045decc>] trace_hardirqs_on_thunk+0x35/0x3a
[<ffffffff8020b6ab>] system_call_after_swapgs+0x7b/0x80

---[ end trace 10ef850597e89c54 ]---


Signed-off-by: Alexey Dobriyan <[email protected]>
---

fs/proc/generic.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -769,7 +769,12 @@ continue_removing:
if (S_ISDIR(de->mode))
parent->nlink--;
de->nlink = 0;
- WARN_ON(de->subdir);
+ if (de->subdir) {
+ printk(KERN_WARNING "%s: removing non-empty directory "
+ "'%s/%s', leaking at least '%s'\n", __func__,
+ de->parent->name, de->name, de->subdir->name);
+ WARN_ON(1);
+ }
if (atomic_dec_and_test(&de->count))
free_proc_entry(de);
break;


2008-02-11 15:39:34

by Arjan van de Ven

[permalink] [raw]
Subject: Re: [PATCH] proc: print more information when removing non-empty directories

Alexey Dobriyan wrote:
> This usually saves one recompile to insert similar printk like below. :)
>
> Sample nastygram:


looks very useful to me!