Re: [BUG] powerpc/bpf: Kernel stack corruption in avc_has_perm() during BPF kselftests (test_progs)

[Venkat Rao Bagalkote]

On 16/09/26 2:22 pm, Shrikanth Hegde wrote:
> Hi Venkat.
>
> Thanks for reporting.
>
> On 9/16/26 2:11 PM, Venkat Rao Bagalkote wrote:
> > Hello All!!!
> >
> >
> > IBM CI has reported a kernel panic on PowerPC (ppc64le, POWER9 
> > pSeries guest) while running BPF kselftests (test_progs).
>
> What has changed in CI that it is hitting now?


Nothings in specific. Its just that, some of the tests were not run for 
some time, due to build and other issues.

> > Environment:
>
> It is very likely same as
> https://lore.kernel.org/all/ba9759d0-b1f2-4b33-aff5-769cf89bd584@xxxxxxxxxxxxx/ 
>
>
> > Kernel version: 7.3.0-rc3-gf6e7b42bf05b (PREEMPT)
> > Architecture: ppc64le (POWER9 - IBM,8375-42A pSeries / phyp)
> > Test Suite: Avocado FVT / kselftests 
> > (tools/testing/selftests/bpf/test_progs)
> >
> >
> > Traces:
> >
> > [ 1359.516833] Kernel panic - not syncing: stack-protector: Kernel 
> > stack is corrupted in: avc_has_perm+0x23c/0x240
> > [ 1359.516856] CPU: 0 UID: 0 PID: 49806 Comm: test_progs Tainted: G   
> >    OE K     7.3.0-rc3-gf6e7b42bf05b #1 PREEMPT
> > [ 1359.516866] Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE, 
> > [K]=LIVEPATCH
> > [ 1359.516870] Hardware name: IBM,8375-42A POWER9 (architected) 
> > 0x4e0202 0xf000005 of:IBM,FW950.80 (VL950_131) hv:phyp pSeries
> > [ 1359.516876] Call Trace:
> > [ 1359.516880] [c00000011bc67b10] [c0000000014627c0] 
> > dump_stack_lvl+0x84/0xc0 (unreliable)
> > [ 1359.516890] [c00000011bc67b40] [c000000000234840] vpanic+0x1b4/0x47c
> > [ 1359.516897] [c00000011bc67be0] [c000000000234b44] 
> > do_panic_on_target_cpu+0x0/0x2c
> > [ 1359.516906] [c00000011bc67c00] [c0000000014f8ce8] 
> > __stack_chk_fail+0x48/0x60
> > [ 1359.516913] [c00000011bc67c70] [c00000000092f0bc] 
> > avc_has_perm+0x23c/0x240
> > [ 1359.516920] [c00000011bc67d40] [c000000000936fc0] 
> > selinux_task_getpgid+0x80/0xa0
> > [ 1359.516927] [c00000011bc67d80] [c000000000920190] 
> > security_task_getpgid+0x70/0x1c0
> > [ 1359.516934] [c00000011bc67db0] [c000000000259488] 
> > do_getpgid+0xa8/0xf0
> > [ 1359.516941] [c00000011bc67de0] [c0000000002594f0] 
> > sys_getpgid+0x20/0x30
> > [ 1359.516948] [c00000011bc67e00] [c000000000034670] 
> > system_call_exception+0x160/0x480
> > [ 1359.516957] [c00000011bc67e50] [c00000000000d05c] 
> > system_call_vectored_common+0x15c/0x2ec
> >
> >
> > Please let us know if any further debugging or testing with specific 
> > BPF JIT options is needed.
> >
> >
> > Regards,
> >
> > Venkat.