Re: [PATCH RESEND v3 1/3] tracing/synthetic: use union instead of casts

From: kernel test robot
Date: Fri Aug 25 2023 - 04:27:42 EST



Hello,

kernel test robot noticed "BUG:unable_to_handle_page_fault_for_address" on:

commit: e2c9745169808b98f235c09d1366cf8b53ce0d3c ("[PATCH RESEND v3 1/3] tracing/synthetic: use union instead of casts")
url: https://github.com/intel-lab-lkp/linux/commits/Sven-Schnelle/tracing-synthetic-use-union-instead-of-casts/20230817-002758
base: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git 4853c74bd7ab7fdb83f319bd9ace8a08c031e9b6
patch link: https://lore.kernel.org/all/20230816154928.4171614-2-svens@xxxxxxxxxxxxx/
patch subject: [PATCH RESEND v3 1/3] tracing/synthetic: use union instead of casts

in testcase: boot

compiler: clang-16
test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G

(please refer to attached dmesg/kmsg for entire log/backtrace)



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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-lkp/202308251530.5bd302e0-oliver.sang@xxxxxxxxx



[ 64.204176][ T48] Dumping ftrace buffer:
[ 64.204632][ T48] ---------------------------------
[ 64.205082][ T48] BUG: unable to handle page fault for address: 001c24ca
[ 64.205641][ T48] #PF: supervisor read access in kernel mode
[ 64.206115][ T48] #PF: error_code(0x0000) - not-present page
[ 64.206588][ T48] *pde = 00000000
[ 64.206897][ T48] Oops: 0000 [#1] SMP
[ 64.207221][ T48] CPU: 0 PID: 48 Comm: rcu_scale_write Tainted: G T 6.5.0-rc6-00037-ge2c974516980 #1
[ 64.208074][ T48] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 64.208892][ T48] EIP: string+0x98/0x100
[ 64.209237][ T48] Code: 94 c2 75 b4 a1 8c c2 75 b4 40 89 44 24 18 31 d2 eb 0e 47 89 3d 94 c2 75 b4 42 39 54 24 0c 74 32 8b 44 24 08 8d 0c 10 8b 45 08 <0f> b6 04
10 84 c0 74 2c 8b 74 24 18 01 d6 89 35 8c c2 75 b4 3b 0c
[ 64.210761][ T48] EAX: 001c24ca EBX: 000405c2 ECX: b516e406 EDX: 00000000
[ 64.211325][ T48] ESI: ffff0a00 EDI: 00005af2 EBP: b600bcd4 ESP: b600bca8
[ 64.211876][ T48] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00010046
[ 64.212468][ T48] CR0: 80050033 CR2: 001c24ca CR3: 08d2a000 CR4: 000406d0
[ 64.213022][ T48] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[ 64.213577][ T48] DR6: fffe0ff0 DR7: 00000400
[ 64.213945][ T48] Call Trace:
[ 64.214208][ T48] ? __die_body+0x69/0xc0
[ 64.214546][ T48] ? __die+0x7e/0x90
[ 64.214863][ T48] ? page_fault_oops+0x22d/0x2b0
[ 64.215242][ T48] ? is_prefetch+0x4a/0x220
[ 64.215605][ T48] ? kernelmode_fixup_or_oops+0xfa/0x140
[ 64.216051][ T48] ? __bad_area_nosemaphore+0x64/0x2a0
[ 64.216485][ T48] ? bad_area_nosemaphore+0x12/0x20
[ 64.216899][ T48] ? do_user_addr_fault+0x650/0x7e0
[ 64.217313][ T48] ? pvclock_clocksource_read_nowd+0x7c/0x230
[ 64.217800][ T48] ? exc_page_fault+0xc5/0x358
[ 64.218183][ T48] ? pvclock_clocksource_read_nowd+0x230/0x230
[ 64.218666][ T48] ? handle_exception+0x14b/0x14b
[ 64.219059][ T48] ? number+0x9b/0x630
[ 64.219378][ T48] ? pvclock_clocksource_read_nowd+0x230/0x230
[ 64.219866][ T48] ? string+0x98/0x100
[ 64.220187][ T48] ? pvclock_clocksource_read_nowd+0x230/0x230
[ 64.220656][ T48] ? string+0x98/0x100
[ 64.220986][ T48] vsnprintf+0x420/0x580
[ 64.221323][ T48] ? vsnprintf+0x3e7/0x580
[ 64.221669][ T48] seq_buf_vprintf+0x79/0xc0
[ 64.222029][ T48] trace_seq_printf+0x35/0xa0
[ 64.222400][ T48] print_synth_event+0x26f/0x300
[ 64.222805][ T48] ? trace_event_raw_event_synth+0x410/0x410
[ 64.223272][ T48] print_trace_fmt+0xfe/0x170
[ 64.223651][ T48] print_trace_line+0x10d/0x1c0
[ 64.224046][ T48] ftrace_dump+0x2fa/0x410
[ 64.224407][ T48] rcu_scale_writer+0x59c/0x640
[ 64.224808][ T48] kthread+0x158/0x170
[ 64.225146][ T48] ? rcu_scale_reader+0x180/0x180
[ 64.225559][ T48] ? kthread_unuse_mm+0x160/0x160
[ 64.225968][ T48] ? kthread_unuse_mm+0x160/0x160
[ 64.226379][ T48] ret_from_fork+0x43/0x70
[ 64.226742][ T48] ret_from_fork_asm+0x12/0x1c
[ 64.227130][ T48] entry_INT80_32+0x108/0x108
[ 64.227516][ T48] Modules linked in:
[ 64.227832][ T48] CR2: 00000000001c24ca
[ 64.228166][ T48] ---[ end trace 0000000000000000 ]---
[ 64.228586][ T48] EIP: string+0x98/0x100
[ 64.228921][ T48] Code: 94 c2 75 b4 a1 8c c2 75 b4 40 89 44 24 18 31 d2 eb 0e 47 89 3d 94 c2 75 b4 42 39 54 24 0c 74 32 8b 44 24 08 8d 0c 10 8b 45 08 <0f> b6 04
10 84 c0 74 2c 8b 74 24 18 01 d6 89 35 8c c2 75 b4 3b 0c
[ 64.230401][ T48] EAX: 001c24ca EBX: 000405c2 ECX: b516e406 EDX: 00000000
[ 64.230918][ T48] ESI: ffff0a00 EDI: 00005af2 EBP: b600bcd4 ESP: b600bca8
[ 64.231432][ T48] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00010046
[ 64.231993][ T48] CR0: 80050033 CR2: 001c24ca CR3: 08d2a000 CR4: 000406d0
[ 64.232527][ T48] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[ 64.233094][ T48] DR6: fffe0ff0 DR7: 00000400
[ 64.233474][ T48] Kernel panic - not syncing: Fatal exception
[ 64.234050][ T48] Kernel Offset: disabled



The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20230825/202308251530.5bd302e0-oliver.sang@xxxxxxxxx



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0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki