diff options
| author | Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> | 2015-10-07 13:50:43 -0700 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-10-08 21:47:13 +0200 |
| commit | e25303676e18a7947185a34e26dd08cf0c0ea573 (patch) | |
| tree | 807d723d722280a5fed31539de17e3b17cb844e8 | |
| parent | 049e6dde7e57f0054fdc49102e7ef4830c698b46 (diff) | |
cpufreq: acpi_cpufreq: prevent crash on reading freqdomain_cpus
When freqdomain_cpus attribute is read from an offlined cpu, it will
cause crash. This change prevents calling cpufreq_show_cpus when
policy driver_data is NULL.
Crash info:
[ 170.814949] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
[ 170.814990] IP: [<ffffffff813b2490>] _find_next_bit.part.0+0x10/0x70
[ 170.815021] PGD 227d30067 PUD 229e56067 PMD 0
[ 170.815043] Oops: 0000 [#2] SMP
[ 170.816022] CPU: 3 PID: 3121 Comm: cat Tainted: G D OE 4.3.0-rc3+ #33
...
...
[ 170.816657] Call Trace:
[ 170.816672] [<ffffffff813b2505>] ? find_next_bit+0x15/0x20
[ 170.816696] [<ffffffff8160e47c>] cpufreq_show_cpus+0x5c/0xd0
[ 170.816722] [<ffffffffa031a409>] show_freqdomain_cpus+0x19/0x20 [acpi_cpufreq]
[ 170.816749] [<ffffffff8160e65b>] show+0x3b/0x60
[ 170.816769] [<ffffffff8129b31c>] sysfs_kf_seq_show+0xbc/0x130
[ 170.816793] [<ffffffff81299be3>] kernfs_seq_show+0x23/0x30
[ 170.816816] [<ffffffff81240f2c>] seq_read+0xec/0x390
[ 170.816837] [<ffffffff8129a64a>] kernfs_fop_read+0x10a/0x160
[ 170.816861] [<ffffffff8121d9b7>] __vfs_read+0x37/0x100
[ 170.816883] [<ffffffff813217c0>] ? security_file_permission+0xa0/0xc0
[ 170.816909] [<ffffffff8121e2e3>] vfs_read+0x83/0x130
[ 170.816930] [<ffffffff8121f035>] SyS_read+0x55/0xc0
...
...
[ 170.817185] ---[ end trace bc6eadf82b2b965a ]---
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.2+ <stable@vger.kernel.org> # 4.2+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
| -rw-r--r-- | drivers/cpufreq/acpi-cpufreq.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c index 798277227de7..cec1ee2d2f74 100644 --- a/drivers/cpufreq/acpi-cpufreq.c +++ b/drivers/cpufreq/acpi-cpufreq.c @@ -149,6 +149,9 @@ static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf) { struct acpi_cpufreq_data *data = policy->driver_data; + if (unlikely(!data)) + return -ENODEV; + return cpufreq_show_cpus(data->freqdomain_cpus, buf); } |