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authorTakashi Iwai <tiwai@suse.de>2014-07-15 08:51:27 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-28 07:06:46 -0700
commit5dc1c8851364ffb79cb9403f72c712ee83cce755 (patch)
parent299e667e26e9e3382fa471370121b117fa8ae987 (diff)
PM / sleep: Fix request_firmware() error at resume
commit 4320f6b1d9db4ca912c5eb6ecb328b2e090e1586 upstream. The commit [247bc037: PM / Sleep: Mitigate race between the freezer and request_firmware()] introduced the finer state control, but it also leads to a new bug; for example, a bug report regarding the firmware loading of intel BT device at suspend/resume: https://bugzilla.novell.com/show_bug.cgi?id=873790 The root cause seems to be a small window between the process resume and the clear of usermodehelper lock. The request_firmware() function checks the UMH lock and gives up when it's in UMH_DISABLE state. This is for avoiding the invalid f/w loading during suspend/resume phase. The problem is, however, that usermodehelper_enable() is called at the end of thaw_processes(). Thus, a thawed process in between can kick off the f/w loader code path (in this case, via btusb_setup_intel()) even before the call of usermodehelper_enable(). Then usermodehelper_read_trylock() returns an error and request_firmware() spews WARN_ON() in the end. This oneliner patch fixes the issue just by setting to UMH_FREEZING state again before restarting tasks, so that the call of request_firmware() will be blocked until the end of this function instead of returning an error. Fixes: 247bc0374254 (PM / Sleep: Mitigate race between the freezer and request_firmware()) Link: https://bugzilla.novell.com/show_bug.cgi?id=873790 Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/power/process.c b/kernel/power/process.c
index 19db29f67558..f27d0c8cd9e8 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -185,6 +185,7 @@ void thaw_processes(void)
printk("Restarting tasks ... ");
+ __usermodehelper_set_disable_depth(UMH_FREEZING);