Messages in this thread Patch in this message | | | From | Sasha Levin <> | Date | Sun, 1 Apr 2012 19:33:56 +0200 | Subject | Re: ipv6: tunnel: hang when destroying ipv6 tunnel |
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On Sun, Apr 1, 2012 at 5:21 AM, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> wrote: > Sasha Levin wrote: >> While it seems that 9p is the culprit, I have to point out that this >> bug is easily reproducible, and it happens each time due to a >> call_usermode_helper() call. Other than that 9p behaves perfectly and >> I'd assume that I'd be seeing other things break besides >> call_usermode_helper() related ones. > > I think one of below two patches can catch the bug if this is a usermodehelper > related bug. Please try. > > ----- Patch 1 ----- > diff --git a/kernel/kmod.c b/kernel/kmod.c > index 01394b6..3e63319 100644 > --- a/kernel/kmod.c > +++ b/kernel/kmod.c > @@ -571,7 +571,7 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) > * flag, for khelper thread is already waiting for the thread at > * wait_for_completion() in do_fork(). > */ > - if (wait != UMH_NO_WAIT && current == kmod_thread_locker) { > + if (WARN_ON(wait != UMH_NO_WAIT && current == kmod_thread_locker)) { > retval = -EBUSY; > goto out; > } > > > ----- Patch 2 ----- > diff --git a/include/linux/kmod.h b/include/linux/kmod.h > index 9efeae6..1350670 100644 > --- a/include/linux/kmod.h > +++ b/include/linux/kmod.h > @@ -48,10 +48,10 @@ static inline int request_module_nowait(const char *name, ...) { return -ENOSYS; > struct cred; > struct file; > > -#define UMH_NO_WAIT 0 /* don't wait at all */ > -#define UMH_WAIT_EXEC 1 /* wait for the exec, but not the process */ > -#define UMH_WAIT_PROC 2 /* wait for the process to complete */ > -#define UMH_KILLABLE 4 /* wait for EXEC/PROC killable */ > +#define UMH_NO_WAIT 0x10 /* don't wait at all */ > +#define UMH_WAIT_EXEC 0x11 /* wait for the exec, but not the process */ > +#define UMH_WAIT_PROC 0x12 /* wait for the process to complete */ > +#define UMH_KILLABLE 0x04 /* wait for EXEC/PROC killable */ > > struct subprocess_info { > struct work_struct work; > diff --git a/kernel/kmod.c b/kernel/kmod.c > index 957a7aa..ecfd3d5 100644 > --- a/kernel/kmod.c > +++ b/kernel/kmod.c > @@ -483,6 +483,18 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) > DECLARE_COMPLETION_ONSTACK(done); > int retval = 0; > > + if (unlikely(wait == -1 || wait == 0 || wait == 1)) { > + WARN(1, "Requesting for usermode helper with hardcoded wait " > + "flag. Change to use UMH_* symbols and recompile, or " > + "this request will fail on Linux 3.4.\n"); > + if (wait == -1) > + wait = UMH_NO_WAIT; > + else if (wait == 0) > + wait = UMH_WAIT_EXEC; > + else > + wait = UMH_WAIT_PROC; > + } > + > helper_lock(); > if (sub_info->path[0] == '\0') > goto out;
Neither of these patches did the trick (no warnings showing up and still seeing the hangs). However, the following patch has fixed it:
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index 1a91efa..8ecc377 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -309,7 +309,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, goto exit;
retval = call_usermodehelper(argv[0], argv, - env->envp, UMH_WAIT_EXEC); + env->envp, UMH_NO_WAIT); }
exit: Not sure if that info helps any, but just in case. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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