Bug 4406 - Yocto-linux-rt: BUG() warning is triggered in rt kernel when run 'perf top' command on ARM/PowerPC
Summary: Yocto-linux-rt: BUG() warning is triggered in rt kernel when run 'perf top' c...
Status: RESOLVED FIXED
Alias: None
Product: General Runtime
Classification: Runtime
Component: General Runtime (show other bugs)
Version: unspecified
Hardware: x86 Multiple
: Medium normal
Target Milestone: 1.5 M2
Assignee: Xufeng Zhang
QA Contact:
URL:
Whiteboard:
Depends on:
Blocks:
 
Reported: 2013-04-24 07:34 UTC by Xufeng Zhang
Modified: 2014-04-24 03:21 UTC (History)
1 user (show)

See Also:
OS type for building Yocto: ---
Type of Regression: ---
Verified:
Documentation change: No (bug/feature does not impact docs)

Attachments
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Xufeng Zhang 2013-04-24 07:34:47 UTC 
This problem is detected on ARM and PowerPC platforms when run "perf top" command
after CONFIG_DEBUG_ATOMIC_SLEEP is enabled in rt kernel.

Call Trace on ARM:
BUG: sleeping function called from invalid context at linux/kernel/rtmutex.c:658
in_atomic(): 1, irqs_disabled(): 128, pid: 1731, name: perf
[<80017d6c>] (unwind_backtrace+0x0/0x104) from [<806416c4>] (dump_stack+0x20/0x24)
[<806416c4>] (dump_stack+0x20/0x24) from [<80061208>] (__might_sleep+0xf4/0x108)
[<80061208>] (__might_sleep+0xf4/0x108) from [<8064a74c>] (rt_spin_lock+0x2c/0x38)
[<8064a74c>] (rt_spin_lock+0x2c/0x38) from [<800642e8>] (__wake_up+0x34/0x60)
[<800642e8>] (__wake_up+0x34/0x60) from [<800e2610>] (perf_event_wakeup+0x40/0x84)
[<800e2610>] (perf_event_wakeup+0x40/0x84) from [<800e2690>] (perf_pending_event+0x3c/0x60)
[<800e2690>] (perf_pending_event+0x3c/0x60) from [<800dd36c>] (irq_work_run+0x74/0xa4)
[<800dd36c>] (irq_work_run+0x74/0xa4) from [<8001b018>] (armv7pmu_handle_irq+0x12c/0x19c)
[<8001b018>] (armv7pmu_handle_irq+0x12c/0x19c) from [<800a87b0>] (handle_irq_event_percpu+0xf0/0x438)
[<800a87b0>] (handle_irq_event_percpu+0xf0/0x438) from [<800a8b70>] (handle_irq_event+0x78/0xa0)
[<800a8b70>] (handle_irq_event+0x78/0xa0) from [<800abdac>] (handle_fasteoi_irq+0xd4/0x18c)
[<800abdac>] (handle_fasteoi_irq+0xd4/0x18c) from [<800a7e70>] (generic_handle_irq+0x40/0x50)
[<800a7e70>] (generic_handle_irq+0x40/0x50) from [<8000f7a4>] (handle_IRQ+0x68/0xbc)
[<8000f7a4>] (handle_IRQ+0x68/0xbc) from [<800084e8>] (gic_handle_irq+0x38/0x68)
[<800084e8>] (gic_handle_irq+0x38/0x68) from [<8064b100>] (__irq_svc+0x40/0x70)

Call Trace on PowerPC:
BUG: sleeping function called from invalid context at linux/kernel/rtmutex.c:658
in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/0
Call Trace:
[c0c0fd80] [c040a1b4] show_stack+0x10c/0x1c0 (unreliable)
[c0c0fdd0] [c09c3c48] dump_stack+0x24/0x34
[c0c0fde0] [c045f728] __might_sleep+0xd8/0xfc
[c0c0fdf0] [c09bb750] rt_spin_lock+0x34/0x7c
[c0c0fe00] [c0462e44] __wake_up+0x38/0x70
[c0c0fe20] [c04df740] perf_event_wakeup+0x40/0x90
[c0c0fe50] [c04df7d0] perf_pending_event+0x40/0x6c
[c0c0fe60] [c04da4d4] irq_work_run+0x84/0xc4
[c0c0fe80] [c040bd54] timer_interrupt+0x1ec/0x3d0
[c0c0fec0] [c0411728] ret_from_except+0x0/0x18

We can run the irq-work under softirq context to resolve this problemjust like x86 does.
Comment 1 Darren Hart 2013-04-25 14:44:57 UTC 
Xufeng if you will be working this, please move the status to "Accepted" and review the Target Milestone. For a change like this, an earlier milestone is preferred to a later one.
Comment 2 Xufeng Zhang 2014-04-24 03:21:46 UTC 
Patch has already been merged.