Oops (NULL pointer) with 'perf record' of selftest 'null_syscall'

[Christophe Leroy]

For your information, I'm getting the following Oops. Detected with 5.13-rc6, it also oopses on 5.12 
and 5.11.
Runs ok on 5.10. I'm starting bisecting now.

root at vgoippro:/tmp# perf record /root/null_syscall
[  285.559987] BUG: Kernel NULL pointer dereference on read at 0x00000040
[  285.566533] Faulting instruction address: 0xc0021f0c
[  285.571486] Oops: Kernel access of bad area, sig: 11 [#1]
[  285.576872] BE PAGE_SIZE=4K PREEMPT CMPCPRO
[  285.581080] SAF3000 DIE NOTIFICATION
[  285.584661] CPU: 0 PID: 442 Comm: null_syscall Not tainted 5.13.0-rc6-s3k-dev-01645-g7649ee3d2957 
#5164
[  285.594035] NIP:  c0021f0c LR: c00e8ad8 CTR: c00d8a5c
[  285.599074] REGS: e67757d0 TRAP: 0300   Not tainted  (5.13.0-rc6-s3k-dev-01645-g7649ee3d2957)
[  285.607576] MSR:  00001032 <ME,IR,DR,RI>  CR: 44775b18  XER: 20000000
[  285.614063] DAR: 00000040 DSISR: 20000000
[  285.614063] GPR00: c00e8810 e6775880 c1c52640 e6775b20 7cb36ae0 f0000028 43ebeedc 5ccc47d0
[  285.614063] GPR08: 00000000 00000900 e6775b20 00000001 00000000 1025b2c0 10013088 10012ee0
[  285.614063] GPR16: b0000000 00000007 00000001 c00deb64 00000042 00000001 78db7b23 c0b13200
[  285.614063] GPR24: 00000000 00000000 00000000 e6775b20 c13b8560 00000107 e6775940 e67758e8
[  285.651693] NIP [c0021f0c] perf_instruction_pointer+0x10/0x60
[  285.657460] LR [c00e8ad8] perf_prepare_sample+0x344/0x674
[  285.662859] Call Trace:
[  285.665301] [e6775880] [c00e8810] perf_prepare_sample+0x7c/0x674 (unreliable)
[  285.672452] [e67758c0] [c00e8e44] perf_event_output_forward+0x3c/0x94
[  285.678903] [e6775910] [c00dea8c] __perf_event_overflow+0x74/0x14c
[  285.685108] [e6775930] [c00dec5c] perf_swevent_hrtimer+0xf8/0x170
[  285.691217] [e6775a40] [c008c8d0] __hrtimer_run_queues.constprop.0+0x160/0x318
[  285.698456] [e6775a90] [c008d94c] hrtimer_interrupt+0x148/0x3b0
[  285.704394] [e6775ae0] [c000c0c0] timer_interrupt+0xc4/0x22c
[  285.710067] [e6775b10] [c00046f0] Decrementer_virt+0xb8/0xbc
[  285.715744] --- interrupt: 900 at pagecache_get_page+0x210/0x430
[  285.721764] NIP:  c00f52a8 LR: c00f5408 CTR: c00f59d8
[  285.726805] REGS: e6775b20 TRAP: 0900   Not tainted  (5.13.0-rc6-s3k-dev-01645-g7649ee3d2957)
[  285.735306] MSR:  00009032 <EE,ME,IR,DR,RI>  CR: 28422d68  XER: 00000000
[  285.742056]
[  285.742056] GPR00: c00f513c e6775bd0 c1c52640 c1c52640 00000000 00000000 00000000 c1382c38
[  285.742056] GPR08: 00000000 00000000 00000001 00000000 88482d68 1025b2c0 10013088 10012ee0
[  285.742056] GPR16: b0000000 00000007 00000001 10012ee0 c18187ac c0b87800 61c88647 c0c18c00
[  285.742056] GPR24: 00000001 00000003 00000000 00000002 c18187a8 00100cca 00000044 00000000
[  285.777079] NIP [c00f52a8] pagecache_get_page+0x210/0x430
[  285.782482] LR [c00f5408] pagecache_get_page+0x370/0x430
[  285.787796] --- interrupt: 900
[  285.790843] [e6775bd0] [c00f513c] pagecache_get_page+0xa4/0x430 (unreliable)
[  285.797910] [e6775c30] [c00f5ca8] filemap_fault+0x2d0/0x8e8
[  285.803500] [e6775ca0] [c012d244] __do_fault+0x4c/0xd8
[  285.808666] [e6775cb0] [c0130f64] handle_mm_fault+0x274/0x10b8
[  285.814517] [e6775d30] [c0014f58] do_page_fault+0x1d4/0x67c
[  285.820117] [e6775d60] [c000424c] DataAccess_virt+0xd4/0xe4
[  285.825707] --- interrupt: 300 at __arch_clear_user+0x10/0xcc
[  285.831458] NIP:  c001a3cc LR: c01d5cfc CTR: 00000000
[  285.836497] REGS: e6775d70 TRAP: 0300   Not tainted  (5.13.0-rc6-s3k-dev-01645-g7649ee3d2957)
[  285.845000] MSR:  00009032 <EE,ME,IR,DR,RI>  CR: 48004264  XER: 20000000
[  285.851751] DAR: 10012ee0 DSISR: 22000000
[  285.851751] GPR00: c01d53fc e6775e20 c1c52640 00000000 00000120 00000008 c136241c 00000000
[  285.851751] GPR08: 00000000 9ffed120 10012ee0 00000004 28004868 1025b2c0 10013088 10012ee0
[  285.851751] GPR16: b0000000 00000007 00000001 10012ee0 10000000 10012d0c 10000000 c1d74240
[  285.851751] GPR24: 10012ee0 00000000 c1345e80 c1343dc0 10000b38 00000000 c132ec00 c1386a00
[  285.889384] NIP [c001a3cc] __arch_clear_user+0x10/0xcc
[  285.894527] LR [c01d5cfc] load_elf_binary+0xec4/0x1340
[  285.899682] --- interrupt: 300
[  285.902730] [e6775e20] [c01d53fc] load_elf_binary+0x5c4/0x1340 (unreliable)
[  285.909713] [e6775ea0] [c0163258] bprm_execve+0x200/0x55c
[  285.915138] [e6775ef0] [c0163e00] do_execveat_common+0x178/0x1f4
[  285.921162] [e6775f20] [c0165558] sys_execve+0x40/0x58
[  285.926321] [e6775f40] [c001404c] ret_from_syscall+0x0/0x28
[  285.931917] --- interrupt: c00 at 0xfc3ce78
[  285.936097] NIP:  0fc3ce78 LR: 0fc3d7cc CTR: c01657cc
[  285.941135] REGS: e6775f50 TRAP: 0c00   Not tainted  (5.13.0-rc6-s3k-dev-01645-g7649ee3d2957)
[  285.949636] MSR:  0000d032 <EE,PR,ME,IR,DR,RI>  CR: 22004868  XER: 20000000
[  285.956655]
[  285.956655] GPR00: 0000000b afab1bf0 a7d77a50 afab6ee1 afab64c8 104bd9b0 fefefeff 7f7f7f7f
[  285.956655] GPR08: afab6ee0 00000000 006df8f9 0000011d 24004864 1025b2c0 10231a50 10249108
[  285.956655] GPR16: 104beeb0 10254830 105dd3f4 10250000 1018a124 10188448 10234e58 00000000
[  285.956655] GPR24: 10231ae0 00000003 00000001 104bd9b0 afab64c8 afab6ee1 0fd25244 afab1bf0
[  285.991684] NIP [0fc3ce78] 0xfc3ce78
[  285.995257] LR [0fc3d7cc] 0xfc3d7cc
[  285.998742] --- interrupt: c00
[  286.001789] Instruction dump:
[  286.004757] 3d20c07d 80a40010 3889847c 486bc444 80630084 546397fe 38630001 4e800020
[  286.012556] 3d20c0b9 7c6a1b78 810915e4 812300a0 <81080040> 55290036 2c090f00 5508056a
[  286.020531] ---[ end trace e381e6fcc2db5226 ]---