From 4320f6b1d9db4ca912c5eb6ecb328b2e090e1586 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 15 Jul 2014 08:51:27 +0200 Subject: PM / sleep: Fix request_firmware() error at resume 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 Cc: 3.4+ # 3.4+ Signed-off-by: Takashi Iwai Signed-off-by: Rafael J. Wysocki --- kernel/power/process.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/power/process.c b/kernel/power/process.c index 0ca8d83e2369..4ee194eb524b 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -186,6 +186,7 @@ void thaw_processes(void) printk("Restarting tasks ... "); + __usermodehelper_set_disable_depth(UMH_FREEZING); thaw_workqueues(); read_lock(&tasklist_lock); -- cgit v1.2.3 From 653a3538f865d26350727df25397bee2bacde773 Mon Sep 17 00:00:00 2001 From: Zhang Rui Date: Tue, 15 Jul 2014 14:26:13 +0200 Subject: PM / sleep: fix freeze_ops NULL pointer dereferences This patch fixes a NULL pointer dereference issue introduced by commit 1f0b63866fc1 (ACPI / PM: Hold ACPI scan lock over the "freeze" sleep state). Fixes: 1f0b63866fc1 (ACPI / PM: Hold ACPI scan lock over the "freeze" sleep state) Link: http://marc.info/?l=linux-pm&m=140541182017443&w=2 Reported-and-tested-by: Alexander Stein Signed-off-by: Zhang Rui Signed-off-by: Rafael J. Wysocki --- kernel/power/suspend.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 4dd8822f732a..ed35a4790afe 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -306,7 +306,7 @@ int suspend_devices_and_enter(suspend_state_t state) error = suspend_ops->begin(state); if (error) goto Close; - } else if (state == PM_SUSPEND_FREEZE && freeze_ops->begin) { + } else if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin) { error = freeze_ops->begin(); if (error) goto Close; @@ -335,7 +335,7 @@ int suspend_devices_and_enter(suspend_state_t state) Close: if (need_suspend_ops(state) && suspend_ops->end) suspend_ops->end(); - else if (state == PM_SUSPEND_FREEZE && freeze_ops->end) + else if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end) freeze_ops->end(); return error; -- cgit v1.2.3