| Message ID | 20161017154112.1111-1-sergey.senozhatsky@gmail.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On 18-10-16, 00:41, Sergey Senozhatsky wrote: > 'best' is always less or equals to 'pos', so `best - pos' returns > a negative value which is then getting casted to `unsigned int' > and passed to __cpufreq_driver_target()->acpi_cpufreq_target() > for policy->freq_table selection. This results in > > BUG: unable to handle kernel paging request at ffff881019b469f8 > IP: [<ffffffffa00356c1>] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq] > PGD 267f067 > PUD 0 > > Oops: 0000 [#1] PREEMPT SMP > CPU: 6 PID: 70 Comm: kworker/6:1 Not tainted 4.9.0-rc1-next-20161017-dbg-dirty > Workqueue: events dbs_work_handler > task: ffff88041b808000 task.stack: ffff88041b810000 > RIP: 0010:[<ffffffffa00356c1>] [<ffffffffa00356c1>] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq] > RSP: 0018:ffff88041b813c60 EFLAGS: 00010282 > RAX: ffff880419b46a00 RBX: ffff88041b848400 RCX: ffff880419b20f80 > RDX: 00000000001dff38 RSI: 00000000ffffffff RDI: ffff88041b848400 > RBP: ffff88041b813cb0 R08: 0000000000000006 R09: 0000000000000040 > R10: ffffffff8207f9e0 R11: ffffffff8173595b R12: 0000000000000000 > R13: ffff88041f1dff38 R14: 0000000000262900 R15: 0000000bfffffff4 > FS: 0000000000000000(0000) GS:ffff88041f000000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffff881019b469f8 CR3: 000000041a2d3000 CR4: 00000000001406e0 > Stack: > ffff88041b813cb0 ffffffff813347f9 ffff88041b813ca0 ffffffff81334663 > ffff88041f1d4bc0 ffff88041b848400 0000000000000000 0000000000000000 > 0000000000262900 0000000000000000 ffff88041b813d00 ffffffff813355dc > Call Trace: > [<ffffffff813347f9>] ? cpufreq_freq_transition_begin+0xf1/0xfc > [<ffffffff81334663>] ? get_cpu_idle_time+0x97/0xa6 > [<ffffffff813355dc>] __cpufreq_driver_target+0x3b6/0x44e > [<ffffffff81336ca3>] cs_dbs_timer+0x11a/0x135 > [<ffffffff81336fda>] dbs_work_handler+0x39/0x62 > [<ffffffff81057823>] process_one_work+0x280/0x4a5 > [<ffffffff81058719>] worker_thread+0x24f/0x397 > [<ffffffff810584ca>] ? rescuer_thread+0x30b/0x30b > [<ffffffff81418380>] ? nl80211_get_key+0x29/0x36a > [<ffffffff8105d2b7>] kthread+0xfc/0x104 > [<ffffffff8107ceea>] ? put_lock_stats.isra.9+0xe/0x20 > [<ffffffff8105d1bb>] ? kthread_create_on_node+0x3f/0x3f > [<ffffffff814b2092>] ret_from_fork+0x22/0x30 > Code: 56 4d 6b ff 0c 41 55 41 54 53 48 83 ec 28 48 8b 15 ad 1e 00 00 44 8b 41 > 08 48 8b 87 c8 00 00 00 49 89 d5 4e 03 2c c5 80 b2 78 81 <46> 8b 74 38 04 45 > 3b 75 00 75 11 31 c0 83 39 00 0f 84 1c 01 00 > RIP [<ffffffffa00356c1>] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq] > RSP <ffff88041b813c60> > CR2: ffff881019b469f8 > ---[ end trace 16d9fc7a17897d37 ]--- > > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> > --- > include/linux/cpufreq.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h > index 5fa55fc..32dc0cbd 100644 > --- a/include/linux/cpufreq.h > +++ b/include/linux/cpufreq.h > @@ -677,10 +677,10 @@ static inline int cpufreq_table_find_index_dl(struct cpufreq_policy *policy, > if (best == table - 1) > return pos - table; > > - return best - pos; > + return best - table; > } > > - return best - pos; > + return best - table; > } > Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 5fa55fc..32dc0cbd 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -677,10 +677,10 @@ static inline int cpufreq_table_find_index_dl(struct cpufreq_policy *policy, if (best == table - 1) return pos - table; - return best - pos; + return best - table; } - return best - pos; + return best - table; } /* Works only on sorted freq-tables */
'best' is always less or equals to 'pos', so `best - pos' returns a negative value which is then getting casted to `unsigned int' and passed to __cpufreq_driver_target()->acpi_cpufreq_target() for policy->freq_table selection. This results in BUG: unable to handle kernel paging request at ffff881019b469f8 IP: [<ffffffffa00356c1>] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq] PGD 267f067 PUD 0 Oops: 0000 [#1] PREEMPT SMP CPU: 6 PID: 70 Comm: kworker/6:1 Not tainted 4.9.0-rc1-next-20161017-dbg-dirty Workqueue: events dbs_work_handler task: ffff88041b808000 task.stack: ffff88041b810000 RIP: 0010:[<ffffffffa00356c1>] [<ffffffffa00356c1>] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq] RSP: 0018:ffff88041b813c60 EFLAGS: 00010282 RAX: ffff880419b46a00 RBX: ffff88041b848400 RCX: ffff880419b20f80 RDX: 00000000001dff38 RSI: 00000000ffffffff RDI: ffff88041b848400 RBP: ffff88041b813cb0 R08: 0000000000000006 R09: 0000000000000040 R10: ffffffff8207f9e0 R11: ffffffff8173595b R12: 0000000000000000 R13: ffff88041f1dff38 R14: 0000000000262900 R15: 0000000bfffffff4 FS: 0000000000000000(0000) GS:ffff88041f000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff881019b469f8 CR3: 000000041a2d3000 CR4: 00000000001406e0 Stack: ffff88041b813cb0 ffffffff813347f9 ffff88041b813ca0 ffffffff81334663 ffff88041f1d4bc0 ffff88041b848400 0000000000000000 0000000000000000 0000000000262900 0000000000000000 ffff88041b813d00 ffffffff813355dc Call Trace: [<ffffffff813347f9>] ? cpufreq_freq_transition_begin+0xf1/0xfc [<ffffffff81334663>] ? get_cpu_idle_time+0x97/0xa6 [<ffffffff813355dc>] __cpufreq_driver_target+0x3b6/0x44e [<ffffffff81336ca3>] cs_dbs_timer+0x11a/0x135 [<ffffffff81336fda>] dbs_work_handler+0x39/0x62 [<ffffffff81057823>] process_one_work+0x280/0x4a5 [<ffffffff81058719>] worker_thread+0x24f/0x397 [<ffffffff810584ca>] ? rescuer_thread+0x30b/0x30b [<ffffffff81418380>] ? nl80211_get_key+0x29/0x36a [<ffffffff8105d2b7>] kthread+0xfc/0x104 [<ffffffff8107ceea>] ? put_lock_stats.isra.9+0xe/0x20 [<ffffffff8105d1bb>] ? kthread_create_on_node+0x3f/0x3f [<ffffffff814b2092>] ret_from_fork+0x22/0x30 Code: 56 4d 6b ff 0c 41 55 41 54 53 48 83 ec 28 48 8b 15 ad 1e 00 00 44 8b 41 08 48 8b 87 c8 00 00 00 49 89 d5 4e 03 2c c5 80 b2 78 81 <46> 8b 74 38 04 45 3b 75 00 75 11 31 c0 83 39 00 0f 84 1c 01 00 RIP [<ffffffffa00356c1>] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq] RSP <ffff88041b813c60> CR2: ffff881019b469f8 ---[ end trace 16d9fc7a17897d37 ]--- Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> --- include/linux/cpufreq.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)