* [linus:master] [timers/migration] 10a0e6f3d3: BUG:KCSAN:data-race_in__tmigr_cpu_activate/print_report
@ 2025-01-03 8:24 kernel test robot
2025-01-04 20:31 ` Frederic Weisbecker
0 siblings, 1 reply; 2+ messages in thread
From: kernel test robot @ 2025-01-03 8:24 UTC (permalink / raw)
To: Anna-Maria Behnsen
Cc: oe-lkp, lkp, linux-kernel, Thomas Gleixner, Frederic Weisbecker,
oliver.sang
Hello,
kernel test robot noticed "BUG:KCSAN:data-race_in__tmigr_cpu_activate/print_report" on:
commit: 10a0e6f3d3db7dcfe36e578923e5f038f1d2b72a ("timers/migration: Move hierarchy setup into cpuhotplug prepare callback")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
[test failed on linus/master ccb98ccef0e543c2bd4ef1a72270461957f3d8d0]
[test failed on linux-next/master 8155b4ef3466f0e289e8fcc9e6e62f3f4dceeac2]
in testcase: trinity
version:
with following parameters:
runtime: 300s
group: group-00
nr_groups: 5
config: x86_64-randconfig-003-20241231
compiler: gcc-12
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
(please refer to attached dmesg/kmsg for entire log/backtrace)
we observed the issue happens randomly, but keeps clean on parent.
facd40aa5c4699f9 10a0e6f3d3db7dcfe36e578923e
---------------- ---------------------------
fail:runs %reproduction fail:runs
| | |
:48 17% 8:48 dmesg.BUG:KCSAN:data-race_in__tmigr_cpu_activate/print_report
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202501031612.62e0c498-lkp@intel.com
[ 30.027314][ T0] BUG: KCSAN: data-race in __tmigr_cpu_activate / print_report
[ 30.027314][ T0]
[ 30.027314][ T0] write to 0xffff88842fc28004 of 1 bytes by task 0 on cpu 0:
[ 30.027314][ T0] __tmigr_cpu_activate (kernel/time/timer_migration.c:689)
[ 30.027314][ T0] tmigr_cpu_activate (kernel/time/timer_migration.c:713)
[ 30.027314][ T0] timer_clear_idle (kernel/time/timer.c:2380 (discriminator 22))
[ 30.027314][ T0] tick_nohz_restart_sched_tick (kernel/time/tick-sched.c:1097)
[ 30.027314][ T0] tick_nohz_idle_exit (kernel/time/tick-sched.c:1442 kernel/time/tick-sched.c:1483)
[ 30.027314][ T0] do_idle (arch/x86/include/asm/bitops.h:75 include/linux/sched/idle.h:36 kernel/sched/idle.c:346)
[ 30.027314][ T0] cpu_startup_entry (kernel/sched/idle.c:429 (discriminator 1))
[ 30.027314][ T0] kernel_init (init/main.c:1459)
[ 30.027314][ T0] do_initcalls (init/main.c:1333)
[ 30.027314][ T0] clear_bss (arch/x86/kernel/head64.c:381)
[ 30.027314][ T0] reserve_bios_regions (arch/x86/kernel/ebda.c:57)
[ 30.027314][ T0] common_startup_64 (arch/x86/kernel/head_64.S:421)
[ 30.027314][ T0]
[ 30.027314][ T0] read to 0xffff88842fc28004 of 1 bytes by task 0 on cpu 1:
[ 30.027314][ T0] print_report (kernel/kcsan/report.c:395)
[ 30.027314][ T0] kcsan_report_known_origin (kernel/kcsan/report.c:504 kernel/kcsan/report.c:694)
[ 30.027314][ T0] kcsan_setup_watchpoint (kernel/kcsan/core.c:678)
[ 30.027314][ T0] tmigr_next_groupevt (kernel/time/timer_migration.c:576)
[ 30.027314][ T0] tmigr_update_events (kernel/time/timer_migration.c:618 kernel/time/timer_migration.c:853)
[ 30.027314][ T0] tmigr_inactive_up (kernel/time/timer_migration.c:1327)
[ 30.027314][ T0] __walk_groups+0x50/0x77
[ 30.027314][ T0] walk_groups (kernel/time/timer_migration.c:501 (discriminator 9))
[ 30.027314][ T0] __tmigr_cpu_deactivate (kernel/time/timer_migration.c:1351)
[ 30.027314][ T0] tmigr_cpu_deactivate (kernel/time/timer_migration.c:1374)
[ 30.027314][ T0] __get_next_timer_interrupt (kernel/time/timer.c:2192 kernel/time/timer.c:2267)
[ 30.027314][ T0] timer_base_try_to_set_idle (kernel/time/timer.c:2357)
[ 30.027314][ T0] tick_nohz_stop_tick (kernel/time/tick-sched.c:987)
[ 30.027314][ T0] tick_nohz_idle_stop_tick (kernel/time/tick-sched.c:1228)
[ 30.027314][ T0] cpuidle_idle_call (kernel/sched/idle.c:191)
[ 30.027314][ T0] do_idle (kernel/sched/idle.c:334)
[ 30.027314][ T0] cpu_startup_entry (kernel/sched/idle.c:429 (discriminator 1))
[ 30.027314][ T0] common_cpu_up (arch/x86/kernel/smpboot.c:850)
[ 30.027314][ T0] common_startup_64 (arch/x86/kernel/head_64.S:421)
[ 30.027314][ T0]
[ 30.027314][ T0] value changed: 0x00 -> 0x01
[ 30.027314][ T0]
[ 30.027314][ T0] Reported by Kernel Concurrency Sanitizer on:
[ 30.027314][ T0] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G T 6.10.0-rc6-00002-g10a0e6f3d3db #1
[ 30.027314][ T0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 30.027314][ T0] ==================================================================
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250103/202501031612.62e0c498-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [linus:master] [timers/migration] 10a0e6f3d3: BUG:KCSAN:data-race_in__tmigr_cpu_activate/print_report
2025-01-03 8:24 [linus:master] [timers/migration] 10a0e6f3d3: BUG:KCSAN:data-race_in__tmigr_cpu_activate/print_report kernel test robot
@ 2025-01-04 20:31 ` Frederic Weisbecker
0 siblings, 0 replies; 2+ messages in thread
From: Frederic Weisbecker @ 2025-01-04 20:31 UTC (permalink / raw)
To: kernel test robot
Cc: Anna-Maria Behnsen, oe-lkp, lkp, linux-kernel, Thomas Gleixner
Le Fri, Jan 03, 2025 at 04:24:52PM +0800, kernel test robot a écrit :
>
>
> Hello,
>
> kernel test robot noticed "BUG:KCSAN:data-race_in__tmigr_cpu_activate/print_report" on:
>
> commit: 10a0e6f3d3db7dcfe36e578923e5f038f1d2b72a ("timers/migration: Move hierarchy setup into cpuhotplug prepare callback")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
>
> [test failed on linus/master ccb98ccef0e543c2bd4ef1a72270461957f3d8d0]
> [test failed on linux-next/master 8155b4ef3466f0e289e8fcc9e6e62f3f4dceeac2]
>
> in testcase: trinity
> version:
> with following parameters:
>
> runtime: 300s
> group: group-00
> nr_groups: 5
>
>
>
> config: x86_64-randconfig-003-20241231
> compiler: gcc-12
> test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
>
> (please refer to attached dmesg/kmsg for entire log/backtrace)
>
>
> we observed the issue happens randomly, but keeps clean on parent.
>
>
> facd40aa5c4699f9 10a0e6f3d3db7dcfe36e578923e
> ---------------- ---------------------------
> fail:runs %reproduction fail:runs
> | | |
> :48 17% 8:48 dmesg.BUG:KCSAN:data-race_in__tmigr_cpu_activate/print_report
>
>
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <oliver.sang@intel.com>
> | Closes: https://lore.kernel.org/oe-lkp/202501031612.62e0c498-lkp@intel.com
>
>
> [ 30.027314][ T0] BUG: KCSAN: data-race in __tmigr_cpu_activate / print_report
> [ 30.027314][ T0]
> [ 30.027314][ T0] write to 0xffff88842fc28004 of 1 bytes by task 0 on cpu 0:
> [ 30.027314][ T0] __tmigr_cpu_activate (kernel/time/timer_migration.c:689)
> [ 30.027314][ T0] tmigr_cpu_activate (kernel/time/timer_migration.c:713)
> [ 30.027314][ T0] timer_clear_idle (kernel/time/timer.c:2380 (discriminator 22))
> [ 30.027314][ T0] tick_nohz_restart_sched_tick (kernel/time/tick-sched.c:1097)
> [ 30.027314][ T0] tick_nohz_idle_exit (kernel/time/tick-sched.c:1442 kernel/time/tick-sched.c:1483)
> [ 30.027314][ T0] do_idle (arch/x86/include/asm/bitops.h:75 include/linux/sched/idle.h:36 kernel/sched/idle.c:346)
> [ 30.027314][ T0] cpu_startup_entry (kernel/sched/idle.c:429 (discriminator 1))
> [ 30.027314][ T0] kernel_init (init/main.c:1459)
> [ 30.027314][ T0] do_initcalls (init/main.c:1333)
> [ 30.027314][ T0] clear_bss (arch/x86/kernel/head64.c:381)
> [ 30.027314][ T0] reserve_bios_regions (arch/x86/kernel/ebda.c:57)
> [ 30.027314][ T0] common_startup_64 (arch/x86/kernel/head_64.S:421)
> [ 30.027314][ T0]
> [ 30.027314][ T0] read to 0xffff88842fc28004 of 1 bytes by task 0 on cpu 1:
> [ 30.027314][ T0] print_report (kernel/kcsan/report.c:395)
> [ 30.027314][ T0] kcsan_report_known_origin (kernel/kcsan/report.c:504 kernel/kcsan/report.c:694)
> [ 30.027314][ T0] kcsan_setup_watchpoint (kernel/kcsan/core.c:678)
> [ 30.027314][ T0] tmigr_next_groupevt (kernel/time/timer_migration.c:576)
> [ 30.027314][ T0] tmigr_update_events (kernel/time/timer_migration.c:618 kernel/time/timer_migration.c:853)
> [ 30.027314][ T0] tmigr_inactive_up (kernel/time/timer_migration.c:1327)
It looks like the .ignore flag accesses and I think it should be tagged as a
voluntary data_race().
Let me cook a patch for that.
Thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2025-01-03 8:24 [linus:master] [timers/migration] 10a0e6f3d3: BUG:KCSAN:data-race_in__tmigr_cpu_activate/print_report kernel test robot
2025-01-04 20:31 ` Frederic Weisbecker
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