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

[Venkat Rao Bagalkote]

Hello All!!!


IBM CI has reported a kernel panic on PowerPC (ppc64le, POWER9 pSeries 
guest) while running BPF kselftests (test_progs).

Environment:


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.