Messages in this thread | | | Date | Thu, 19 Sep 2013 02:13:04 +0400 | From | Andrew Savchenko <> | Subject | Re: [BUG] 3.7-rc regression bisected: s2disk fails to resume image: Processes could not be frozen, cannot continue resuming |
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On Wed, 18 Sep 2013 20:16:07 +0100 Al Viro wrote: > On Wed, Sep 18, 2013 at 10:40:32PM +0400, Andrew Savchenko wrote: > > > And from suspend_ioctls.h: > > #define SNAPSHOT_IOC_MAGIC '3' > > #define SNAPSHOT_FREEZE _IO(SNAPSHOT_IOC_MAGIC, 1) > > > > My mistake, should be '3' instead of 3. > > OK... The thing to test, then, is what does __usermodehelper_disable() > return to freeze_processes(). If that's where this -EAGAIN comes from, > we at least have a plausible theory re what's going on. > > freeze_processes() uses __usermodehelper_disable() to stop any new userland > processes spawned by UMH (modprobe, etc.) and waits for ones it might be > waiting for to complete. Then it does try_to_freeze_tasks(), which > freezes remaining userland, carefully skipping the current thread. > However, it misses the possibility that current thread might have been > spawned by something that had been launched by UMH, with UMH waiting > for it. Which is the case of everything spawned by linuxrc. > > I'd try something like diff below, but I'm *NOT* familiar with swsusp at > all; it's not for mainline until ACKed by swsusp folks. > > diff --git a/kernel/kmod.c b/kernel/kmod.c > index fb32636..d968882 100644 > --- a/kernel/kmod.c > +++ b/kernel/kmod.c > @@ -571,7 +571,8 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) > DECLARE_COMPLETION_ONSTACK(done); > int retval = 0; > > - helper_lock(); > + if (!(current->flags & PF_FREEZER_SKIP)) > + helper_lock(); > if (!khelper_wq || usermodehelper_disabled) { > retval = -EBUSY; > goto out; > @@ -611,7 +612,8 @@ wait_done: > out: > call_usermodehelper_freeinfo(sub_info); > unlock: > - helper_unlock(); > + if (!(current->flags & PF_FREEZER_SKIP)) > + helper_unlock(); > return retval; > } > EXPORT_SYMBOL(call_usermodehelper_exec);
With this patch and 3.11.1 kernel resume works fine.
Best regards, Andrew Savchenko [unhandled content-type:application/pgp-signature] | |