On Thu, 2020-04-16 at 22:40 -0400, Qian Cai wrote: > > On Apr 16, 2020, at 10:27 PM, Russell Currey <rus...@russell.cc> > > wrote: > > > > Reverting the patch with the given config will have the same effect > > as > > STRICT_KERNEL_RWX=n. Not discounting that it could be a bug on the > > powerpc side (i.e. relocatable kernels with strict RWX on haven't > > been > > exhaustively tested yet), but we should definitely figure out > > what's > > going on with this bad access first. > > BTW, this bad access only happened once. The overwhelming rest of > crashes are with NULL pointer NIP like below. How can you explain > that STRICT_KERNEL_RWX=n would also make those NULL NIP disappear if > STRICT_KERNEL_RWX is just a messenger?
What happens if you test with STRICT_KERNEL_RWX=y and RELOCATABLE=n, reverting my patch? This would give us an idea of whether it's something broken recently or if there's something else going on. > > [ 215.281666][T16896] LTP: starting chown04_16 > [ 215.424203][T18297] BUG: Unable to handle kernel instruction fetch > (NULL pointer?) > [ 215.424289][T18297] Faulting instruction address: 0x00000000 > [ 215.424313][T18297] Oops: Kernel access of bad area, sig: 11 [#1] > [ 215.424341][T18297] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=256 > DEBUG_PAGEALLOC NUMA PowerNV > [ 215.424383][T18297] Modules linked in: loop kvm_hv kvm ip_tables > x_tables xfs sd_mod bnx2x mdio tg3 ahci libahci libphy libata > firmware_class dm_mirror dm_region_hash dm_log dm_mod > [ 215.424459][T18297] CPU: 85 PID: 18297 Comm: chown04_16 Tainted: > G W 5.6.0-next-20200405+ #3 > [ 215.424489][T18297] NIP: 0000000000000000 LR: c00800000fbc0408 > CTR: 0000000000000000 > [ 215.424530][T18297] REGS: c000200b8606f990 TRAP: 0400 Tainted: > G W (5.6.0-next-20200405+) > [ 215.424570][T18297] MSR: 9000000040009033 > <SF,HV,EE,ME,IR,DR,RI,LE> CR: 84000248 XER: 20040000 > [ 215.424619][T18297] CFAR: c00800000fbc64f4 IRQMASK: 0 > [ 215.424619][T18297] GPR00: c0000000006c2238 c000200b8606fc20 > c00000000165ce00 0000000000000000 > [ 215.424619][T18297] GPR04: c000201a58106400 c000200b8606fcc0 > 000000005f037e7d ffffffff00013bfb > [ 215.424619][T18297] GPR08: c000201a58106400 0000000000000000 > 0000000000000000 c000000001652ee0 > [ 215.424619][T18297] GPR12: 0000000000000000 c000201fff69a600 > 0000000000000000 0000000000000000 > [ 215.424619][T18297] GPR16: 0000000000000000 0000000000000000 > 0000000000000000 0000000000000000 > [ 215.424619][T18297] GPR20: 0000000000000000 0000000000000000 > 0000000000000000 0000000000000007 > [ 215.424619][T18297] GPR24: 0000000000000000 0000000000000000 > c00800000fbc8688 c000200b8606fcc0 > [ 215.424619][T18297] GPR28: 0000000000000000 000000007fffffff > c00800000fbc0400 c00020068b8c0e70 > [ 215.424914][T18297] NIP [0000000000000000] 0x0 > [ 215.424953][T18297] LR [c00800000fbc0408] find_free_cb+0x8/0x30 > [loop] > find_free_cb at drivers/block/loop.c:2129 > [ 215.424997][T18297] Call Trace: > [ 215.425036][T18297] [c000200b8606fc20] [c0000000006c2290] > idr_for_each+0xf0/0x170 (unreliable) > [ 215.425073][T18297] [c000200b8606fca0] [c00800000fbc2744] > loop_lookup.part.2+0x4c/0xb0 [loop] > loop_lookup at drivers/block/loop.c:2144 > [ 215.425105][T18297] [c000200b8606fce0] [c00800000fbc3558] > loop_control_ioctl+0x120/0x1d0 [loop] > [ 215.425149][T18297] [c000200b8606fd40] [c0000000004eb688] > ksys_ioctl+0xd8/0x130 > [ 215.425190][T18297] [c000200b8606fd90] [c0000000004eb708] > sys_ioctl+0x28/0x40 > [ 215.425233][T18297] [c000200b8606fdb0] [c00000000003cc30] > system_call_exception+0x110/0x1e0 > [ 215.425274][T18297] [c000200b8606fe20] [c00000000000c9f0] > system_call_common+0xf0/0x278 > [ 215.425314][T18297] Instruction dump: > [ 215.425338][T18297] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX > XXXXXXXX XXXXXXXX XXXXXXXX > [ 215.425374][T18297] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX > XXXXXXXX XXXXXXXX XXXXXXXX > [ 215.425422][T18297] ---[ end trace ebed248fad431966 ]--- > [ 215.642114][T18297] > [ 216.642220][T18297] Kernel panic - not syncing: Fatal exception
