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author | Rafael J. Wysocki <rjw@sisk.pl> | 2009-05-24 19:15:07 (GMT) |
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committer | Rafael J. Wysocki <rjw@sisk.pl> | 2009-05-24 19:15:07 (GMT) |
commit | 32bdfac5462d777f35b00838893c4f87baf23efe (patch) | |
tree | 92e4ef3af7b68007e8004eaca978865a29e543b0 /kernel/power/main.c | |
parent | 59a3759d0fe8d969888c741bb33f4946e4d3750d (diff) | |
download | linux-fsl-qoriq-32bdfac5462d777f35b00838893c4f87baf23efe.tar.xz |
PM: Do not hold dpm_list_mtx while disabling/enabling nonboot CPUs
We shouldn't hold dpm_list_mtx while executing
[disable|enable]_nonboot_cpus(), because theoretically this may lead
to a deadlock as shown by the following example (provided by Johannes
Berg):
CPU 3 CPU 2 CPU 1
suspend/hibernate
something:
rtnl_lock() device_pm_lock()
-> mutex_lock(&dpm_list_mtx)
mutex_lock(&dpm_list_mtx)
linkwatch_work
-> rtnl_lock()
disable_nonboot_cpus()
-> flush CPU 3 workqueue
Fortunately, device drivers are supposed to stop any activities that
might lead to the registration of new device objects way before
disable_nonboot_cpus() is called, so it shouldn't be necessary to
hold dpm_list_mtx over the entire late part of device suspend and
early part of device resume.
Thus, during the late suspend and the early resume of devices acquire
dpm_list_mtx only when dpm_list is going to be traversed and release
it right after that.
This patch is reported to fix the regressions tracked as
http://bugzilla.kernel.org/show_bug.cgi?id=13245.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Miles Lane <miles.lane@gmail.com>
Tested-by: Ming Lei <tom.leiming@gmail.com>
Diffstat (limited to 'kernel/power/main.c')
-rw-r--r-- | kernel/power/main.c | 7 |
1 files changed, 1 insertions, 6 deletions
diff --git a/kernel/power/main.c b/kernel/power/main.c index f99ed6a..8680282 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -289,12 +289,10 @@ static int suspend_enter(suspend_state_t state) { int error; - device_pm_lock(); - if (suspend_ops->prepare) { error = suspend_ops->prepare(); if (error) - goto Done; + return error; } error = device_power_down(PMSG_SUSPEND); @@ -343,9 +341,6 @@ static int suspend_enter(suspend_state_t state) if (suspend_ops->finish) suspend_ops->finish(); - Done: - device_pm_unlock(); - return error; } |