[PATCH V2] powerpc/perf: Fix handling of privilege level checks in perf interrupt context

[Michael Ellerman]

On Thu, 25 Feb 2021 05:10:39 -0500, Athira Rajeev wrote:
> Running "perf mem record" in powerpc platforms with selinux enabled
> resulted in soft lockup's. Below call-trace was seen in the logs:
> 
> CPU: 58 PID: 3751 Comm: sssd_nss Not tainted 5.11.0-rc7+ #2
> NIP:  c000000000dff3d4 LR: c000000000dff3d0 CTR: 0000000000000000
> REGS: c000007fffab7d60 TRAP: 0100   Not tainted  (5.11.0-rc7+)
> <<>>
> NIP [c000000000dff3d4] _raw_spin_lock_irqsave+0x94/0x120
> LR [c000000000dff3d0] _raw_spin_lock_irqsave+0x90/0x120
> Call Trace:
> [c00000000fd471a0] [c00000000fd47260] 0xc00000000fd47260 (unreliable)
> [c00000000fd471e0] [c000000000b5fbbc] skb_queue_tail+0x3c/0x90
> [c00000000fd47220] [c000000000296edc] audit_log_end+0x6c/0x180
> [c00000000fd47260] [c0000000006a3f20] common_lsm_audit+0xb0/0xe0
> [c00000000fd472a0] [c00000000066c664] slow_avc_audit+0xa4/0x110
> [c00000000fd47320] [c00000000066cff4] avc_has_perm+0x1c4/0x260
> [c00000000fd47430] [c00000000066e064] selinux_perf_event_open+0x74/0xd0
> [c00000000fd47450] [c000000000669888] security_perf_event_open+0x68/0xc0
> [c00000000fd47490] [c00000000013d788] record_and_restart+0x6e8/0x7f0
> [c00000000fd476c0] [c00000000013dabc] perf_event_interrupt+0x22c/0x560
> [c00000000fd477d0] [c00000000002d0fc] performance_monitor_exception0x4c/0x60
> [c00000000fd477f0] [c00000000000b378] performance_monitor_common_virt+0x1c8/0x1d0
> interrupt: f00 at _raw_spin_lock_irqsave+0x38/0x120
> NIP:  c000000000dff378 LR: c000000000b5fbbc CTR: c0000000007d47f0
> REGS: c00000000fd47860 TRAP: 0f00   Not tainted  (5.11.0-rc7+)
> <<>>
> NIP [c000000000dff378] _raw_spin_lock_irqsave+0x38/0x120
> LR [c000000000b5fbbc] skb_queue_tail+0x3c/0x90
> interrupt: f00
> [c00000000fd47b00] [0000000000000038] 0x38 (unreliable)
> [c00000000fd47b40] [c00000000aae6200] 0xc00000000aae6200
> [c00000000fd47b80] [c000000000296edc] audit_log_end+0x6c/0x180
> [c00000000fd47bc0] [c00000000029f494] audit_log_exit+0x344/0xf80
> [c00000000fd47d10] [c0000000002a2b00] __audit_syscall_exit+0x2c0/0x320
> [c00000000fd47d60] [c000000000032878] do_syscall_trace_leave+0x148/0x200
> [c00000000fd47da0] [c00000000003d5b4] syscall_exit_prepare+0x324/0x390
> [c00000000fd47e10] [c00000000000d76c] system_call_common+0xfc/0x27c
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/perf: Fix handling of privilege level checks in perf interrupt context
      https://git.kernel.org/powerpc/c/5ae5fbd2107959b68ac69a8b75412208663aea88

cheers