cb57720bf7
If ACPI _PPC changed notification happens before governor was initiated while kernel is booting, a NULL pointer dereference will be triggered: BUG: unable to handle kernel NULL pointer dereference at 0000000000000030 IP: [<ffffffff81470453>] __cpufreq_governor+0x23/0x1e0 PGD 0 Oops: 0000 [#1] SMP ... ... RIP: 0010:[<ffffffff81470453>] [<ffffffff81470453>] __cpufreq_governor+0x23/0x1e0 RSP: 0018:ffff881fcfbcfbb8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff881fd11b3980 RCX: ffff88407fc20000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff881fd11b3980 RBP: ffff881fcfbcfbd8 R08: 0000000000000000 R09: 000000000000000f R10: ffffffff818068d0 R11: 0000000000000043 R12: 0000000000000004 R13: 0000000000000000 R14: ffffffff8196cae0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff881fffc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000030 CR3: 00000000018ae000 CR4: 00000000000407f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process kworker/0:3 (pid: 750, threadinfo ffff881fcfbce000, task ffff881fcf556400) Stack: ffff881fffc17d00 ffff881fcfbcfc18 ffff881fd11b3980 0000000000000000 ffff881fcfbcfc08 ffffffff81470d08 ffff881fd11b3980 0000000000000007 ffff881fcfbcfc18 ffff881fffc17d00 ffff881fcfbcfd28 ffffffff81472e9a Call Trace: [<ffffffff81470d08>] __cpufreq_set_policy+0x1b8/0x2e0 [<ffffffff81472e9a>] cpufreq_update_policy+0xca/0x150 [<ffffffff81472f20>] ? cpufreq_update_policy+0x150/0x150 [<ffffffff81324a96>] acpi_processor_ppc_has_changed+0x71/0x7b [<ffffffff81320bcd>] acpi_processor_notify+0x55/0x115 [<ffffffff812f9c29>] acpi_device_notify+0x19/0x1b [<ffffffff813084ca>] acpi_ev_notify_dispatch+0x41/0x5f [<ffffffff812f64a4>] acpi_os_execute_deferred+0x27/0x34 The root cause is a race conditon -- cpufreq core and acpi-cpufreq driver were initiated, but cpufreq_governor wasn't and _PPC changed notification happened, __cpufreq_governor() was called within acpi_os_execute_deferred kernel thread context. To fix this panic issue, add pointer checking code in __cpufreq_governor() before pointer policy->governor is to be dereferenced. Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
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.. | ||
acpi-cpufreq.c | ||
amd_freq_sensitivity.c | ||
arm_big_little_dt.c | ||
arm_big_little.c | ||
arm_big_little.h | ||
at32ap-cpufreq.c | ||
blackfin-cpufreq.c | ||
cpufreq_conservative.c | ||
cpufreq_governor.c | ||
cpufreq_governor.h | ||
cpufreq_ondemand.c | ||
cpufreq_opp.c | ||
cpufreq_performance.c | ||
cpufreq_powersave.c | ||
cpufreq_stats.c | ||
cpufreq_userspace.c | ||
cpufreq-dt.c | ||
cpufreq-nforce2.c | ||
cpufreq.c | ||
cris-artpec3-cpufreq.c | ||
cris-etraxfs-cpufreq.c | ||
davinci-cpufreq.c | ||
dbx500-cpufreq.c | ||
e_powersaver.c | ||
elanfreq.c | ||
exynos4x12-cpufreq.c | ||
exynos4210-cpufreq.c | ||
exynos5250-cpufreq.c | ||
exynos5440-cpufreq.c | ||
exynos-cpufreq.c | ||
exynos-cpufreq.h | ||
freq_table.c | ||
gx-suspmod.c | ||
highbank-cpufreq.c | ||
ia64-acpi-cpufreq.c | ||
imx6q-cpufreq.c | ||
integrator-cpufreq.c | ||
intel_pstate.c | ||
Kconfig | ||
Kconfig.arm | ||
Kconfig.powerpc | ||
Kconfig.x86 | ||
kirkwood-cpufreq.c | ||
longhaul.c | ||
longhaul.h | ||
longrun.c | ||
loongson2_cpufreq.c | ||
ls1x-cpufreq.c | ||
Makefile | ||
maple-cpufreq.c | ||
omap-cpufreq.c | ||
p4-clockmod.c | ||
pasemi-cpufreq.c | ||
pcc-cpufreq.c | ||
pmac32-cpufreq.c | ||
pmac64-cpufreq.c | ||
powernow-k6.c | ||
powernow-k7.c | ||
powernow-k7.h | ||
powernow-k8.c | ||
powernow-k8.h | ||
powernv-cpufreq.c | ||
ppc_cbe_cpufreq_pervasive.c | ||
ppc_cbe_cpufreq_pmi.c | ||
ppc_cbe_cpufreq.c | ||
ppc_cbe_cpufreq.h | ||
ppc-corenet-cpufreq.c | ||
pxa2xx-cpufreq.c | ||
pxa3xx-cpufreq.c | ||
s3c24xx-cpufreq-debugfs.c | ||
s3c24xx-cpufreq.c | ||
s3c64xx-cpufreq.c | ||
s3c2410-cpufreq.c | ||
s3c2412-cpufreq.c | ||
s3c2416-cpufreq.c | ||
s3c2440-cpufreq.c | ||
s5pv210-cpufreq.c | ||
sa1100-cpufreq.c | ||
sa1110-cpufreq.c | ||
sc520_freq.c | ||
sh-cpufreq.c | ||
sparc-us2e-cpufreq.c | ||
sparc-us3-cpufreq.c | ||
spear-cpufreq.c | ||
speedstep-centrino.c | ||
speedstep-ich.c | ||
speedstep-lib.c | ||
speedstep-lib.h | ||
speedstep-smi.c | ||
tegra-cpufreq.c | ||
unicore2-cpufreq.c | ||
vexpress-spc-cpufreq.c |