WARNING: arch_install_hw_breakpoint+0xe0/0xf8() Can't find any breakpoint slot

Severity

Mild. WARN_ON_ONCE. Does not seem to affect system stability.

Fixed by

Was thought to be gixed by 9fc81d87420d0d3fd62d5e5529972c0ad9eab9cc but the warning still happens.

Found by

perf_fuzzer

Reproducible

yes

Seen On

Core2

First Seen

3.14-rc5. Might have appeared earlier, did not attempt bisection.

Most Recently Seen

3.19, 4.1-rc2

Reported to Mailing List

Yes (since the reported 3.19 fix). Need to find.

Kernel Spews

  1. Stopping after 30000
    Watchdog enabled with timeout 60s
    Will auto-exit if signal storm detected
    
    *** perf_fuzzer 0.30-pre *** by Vince Weaver
    
    	Linux version 3.19.0+ x86_64
    	Processor: Intel 6/23/10
    
    	Seeding random number generator with 1423846760
    	/proc/sys/kernel/perf_event_max_sample_rate currently: 100000/s
    	/proc/sys/kernel/perf_event_paranoid currently: 1
    	Logging perf_event_open() failures: no
    	Running fsync after every syscall: no
    	To reproduce, try: ./perf_fuzzer -s 30000 -r 1423846760
    
    Pid=4504, sleeping 1s
    ==================================================
    Fuzzing the following syscalls:
    	mmap perf_event_open close read write ioctl fork prctl poll 
    *NOT* Fuzzing the following syscalls:
    	
    Also attempting the following:
    	signal-handler-on-overflow busy-instruction-loop accessing-perf-proc-and-sys-files trashing-the-mmap-page 
    *NOT* attempting the following:
    	
    ==================================================
    Iteration 10000
    	Open attempts: 217949  Successful: 1008
    		EPERM : 42
    		ENOENT : 1936
    		E2BIG : 21069
    		EBADF : 8070
    		EACCES : 397
    		EINVAL : 184293
    		EOPNOTSUPP : 1134
    		Type (Hardware 209/28749)(software 404/34316)(tracepoint 124/34344)(Cache 41/27378)(cpu 203/34127)(breakpoint 27/33866)(#6 0/37)(#7 0/19)(#8 0/101)(#9 0/29)(#10 0/33)(#11 0/25)(#12 0/39)(#13 0/32)(#14 0/24)(>14 0/24830)
    	Close attempts: 860  Successful: 860
    	Read attempts: 871  Successful: 777
    	Write attempts: 911  Successful: 0
    	Ioctl attempts: 855  Successful: 397
    	Mmap attempts: 1008  Successful: 293
    	Prctl attempts: 890  Successful: 890
    	Fork attempts: 438  Successful: 438
    	Poll attempts: 880  Successful: 838
    	Access attempts: 882  Successful: 423
    	Trash mmap attempts: 909  Successful: 909
    	Overflows: 28
    	SIGIOs due to RT signal queue full: 0
    Iteration 20000
    	Open attempts: 208916  Successful: 918
    		EPERM : 39
    		ENOENT : 1932
    		E2BIG : 20162
    		EBADF : 7104
    		EACCES : 453
    		EINVAL : 177171
    		ENOSPC : 17
    		EOPNOTSUPP : 1120
    		Type (Hardware 183/27543)(software 371/32907)(tracepoint 112/32871)(Cache 45/26097)(cpu 183/33000)(breakpoint 24/32546)(#6 0/33)(#7 0/21)(#8 0/98)(#9 0/28)(#10 0/22)(#11 0/33)(#12 0/33)(#13 0/23)(#14 0/29)(>14 0/23632)
    	Close attempts: 900  Successful: 900
    	Read attempts: 892  Successful: 744
    	Write attempts: 928  Successful: 0
    	Ioctl attempts: 877  Successful: 420
    	Mmap attempts: 918  Successful: 216
    	Prctl attempts: 913  Successful: 913
    	Fork attempts: 442  Successful: 442
    	Poll attempts: 924  Successful: 912
    	Access attempts: 895  Successful: 438
    	Trash mmap attempts: 934  Successful: 934
    	Overflows: 0
    	SIGIOs due to RT signal queue full: 0
    [ 1484.379859] ------------[ cut here ]------------
    [ 1484.380006] WARNING: CPU: 0 PID: 4504 at arch/x86/kernel/hw_breakpoint.c:119 arch_install_hw_breakpoint+0xe0/0xf8()
    [ 1484.380006] Can't find any breakpoint slot
    [ 1484.380006] Modules linked in: cpufreq_userspace cpufreq_stats cpufreq_powersave cpufreq_conservative f71882fg mcs7830 usbnet evdev video pcspkr acpi_cpufreq coretemp psmouse serio_raw processor thermal_sys ohci_pci ohci_hcd i2c_nforce2 wmi button sg ehci_pci ehci_hcd sd_mod usbcore usb_common
    [ 1484.380006] CPU: 0 PID: 4504 Comm: perf_fuzzer Not tainted 3.19.0+ #201
    [ 1484.380006] Hardware name: AOpen   DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BIOS 080015  10/19/2012
    [ 1484.380006]  0000000000000009 ffff8800c0a03bb8 ffffffff81539683 00000000000024f0
    [ 1484.380006]  ffff8800c0a03c08 ffff8800c0a03bf8 ffffffff8104147b 0000000100000021
    [ 1484.380006]  ffffffff81009560 0000000000000004 ffff88011abaa000 000001571b9a96d7
    [ 1484.380006] Call Trace:
    [ 1484.380006]  [] dump_stack+0x45/0x57
    [ 1484.380006]  [] warn_slowpath_common+0xa1/0xbb
    [ 1484.380006]  [] ? arch_install_hw_breakpoint+0xe0/0xf8
    [ 1484.380006]  [] warn_slowpath_fmt+0x46/0x48
    [ 1484.380006]  [] arch_install_hw_breakpoint+0xe0/0xf8
    [ 1484.380006]  [] hw_breakpoint_add+0x46/0x4a
    [ 1484.380006]  [] event_sched_in+0x87/0x1b0
    [ 1484.380006]  [] group_sched_in+0x7c/0x13c
    [ 1484.380006]  [] __perf_event_enable+0xbb/0xfb
    [ 1484.380006]  [] remote_function+0x18/0x41
    [ 1484.380006]  [] ? perf_event_ctx_unlock.isra.54+0x1e/0x1e
    [ 1484.380006]  [] generic_exec_single+0x3d/0x10d
    [ 1484.380006]  [] ? update_context_time+0xe/0x31
    [ 1484.380006]  [] ? perf_event_ctx_unlock.isra.54+0x1e/0x1e
    [ 1484.380006]  [] smp_call_function_single+0x7f/0x8a
    [ 1484.380006]  [] task_function_call+0x44/0x4e
    [ 1484.380006]  [] ? __perf_install_in_context+0xcd/0xcd
    [ 1484.380006]  [] _perf_event_enable+0x88/0xc0
    [ 1484.380006]  [] ? task_function_call+0x4e/0x4e
    [ 1484.380006]  [] perf_event_for_each_child+0x58/0x93
    [ 1484.380006]  [] perf_event_task_enable+0x62/0x92
    [ 1484.380006]  [] SyS_prctl+0x155/0x375
    [ 1484.380006]  [] system_call_fastpath+0x16/0x1b
    [ 1484.380006] ---[ end trace d1270db1875e1885 ]---
    Iteration 30000
    

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