Qian Cai <c...@lca.pw> writes: > Ever since 1st Apr, linux-next starts to trigger a NULL pointer NIP on POWER9 > below using > this config, > > https://raw.githubusercontent.com/cailca/linux-mm/master/powerpc.config > > It takes a while to reproduce, so before I bury myself into bisecting and > just send a head-up > to see if anyone spots anything obvious. > > [ 206.744625][T13224] LTP: starting fallocate04 > [ 207.601583][T27684] /dev/zero: Can't open blockdev > [ 208.674301][T27684] EXT4-fs (loop0): mounting ext3 file system using the > ext4 subsystem > [ 208.680347][T27684] BUG: Unable to handle kernel instruction fetch (NULL > pointer?) > [ 208.680383][T27684] Faulting instruction address: 0x00000000 > [ 208.680406][T27684] Oops: Kernel access of bad area, sig: 11 [#1] > [ 208.680439][T27684] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=256 > DEBUG_PAGEALLOC NUMA PowerNV > [ 208.680474][T27684] Modules linked in: ext4 crc16 mbcache jbd2 loop kvm_hv > kvm ip_tables x_tables xfs sd_mod bnx2x ahci libahci mdio tg3 libata libphy > firmware_class dm_mirror dm_region_hash dm_log dm_mod > [ 208.680576][T27684] CPU: 117 PID: 27684 Comm: fallocate04 Tainted: G > W 5.6.0-next-20200401+ #288 > [ 208.680614][T27684] NIP: 0000000000000000 LR: c0080000102c0048 CTR: > 0000000000000000 > [ 208.680657][T27684] REGS: c000200361def420 TRAP: 0400 Tainted: G > W (5.6.0-next-20200401+) > [ 208.680700][T27684] MSR: 900000004280b033 > <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 42022228 XER: 20040000 > [ 208.680760][T27684] CFAR: c00800001032c494 IRQMASK: 0 > [ 208.680760][T27684] GPR00: c0000000005ac3f8 c000200361def6b0 > c00000000165c200 c00020107dae0bd0 > [ 208.680760][T27684] GPR04: 0000000000000000 0000000000000400 > 0000000000000000 0000000000000000 > [ 208.680760][T27684] GPR08: c000200361def6e8 c0080000102c0040 > 000000007fffffff c000000001614e80 > [ 208.680760][T27684] GPR12: 0000000000000000 c000201fff671280 > 0000000000000000 0000000000000002 > [ 208.680760][T27684] GPR16: 0000000000000002 0000000000040001 > c00020030f5a1000 c00020030f5a1548 > [ 208.680760][T27684] GPR20: c0000000015fbad8 c00000000168c654 > c000200361def818 c0000000005b4c10 > [ 208.680760][T27684] GPR24: 0000000000000000 c0080000103365b8 > c00020107dae0bd0 0000000000000400 > [ 208.680760][T27684] GPR28: c00000000168c3a8 0000000000000000 > 0000000000000000 0000000000000000 > [ 208.681014][T27684] NIP [0000000000000000] 0x0 > [ 208.681065][T27684] LR [c0080000102c0048] ext4_iomap_end+0x8/0x30 [ext4]
That LR looks like it's pointing to the return from _mcount in ext4_iomap_end(), which means we have probably crashed in ftrace somewhere. Did you have tracing enabled when you ran the test? Or does it do tracing itself? cheers > [ 208.681091][T27684] Call Trace: > [ 208.681129][T27684] [c000200361def6b0] [c0000000005ac3bc] > iomap_apply+0x20c/0x920 (unreliable) iomap_apply at fs/iomap/apply.c:80 > (discriminator 4) > [ 208.681173][T27684] [c000200361def7f0] [c0000000005b4adc] > iomap_bmap+0xfc/0x160 iomap_bmap at fs/iomap/fiemap.c:142 > [ 208.681228][T27684] [c000200361def850] [c0080000102c2c1c] > ext4_bmap+0xa4/0x180 [ext4] ext4_bmap at fs/ext4/inode.c:3213 > [ 208.681260][T27684] [c000200361def890] [c0000000004f71fc] bmap+0x4c/0x80 > [ 208.681281][T27684] [c000200361def8c0] [c00800000fdb0acc] > jbd2_journal_init_inode+0x44/0x1a0 [jbd2] jbd2_journal_init_inode at > fs/jbd2/journal.c:1255 > [ 208.681326][T27684] [c000200361def960] [c00800001031c808] > ext4_load_journal+0x440/0x860 [ext4] > [ 208.681371][T27684] [c000200361defa30] [c008000010322a14] > ext4_fill_super+0x342c/0x3ab0 [ext4] > [ 208.681414][T27684] [c000200361defba0] [c0000000004cb0bc] > mount_bdev+0x25c/0x290 > [ 208.681478][T27684] [c000200361defc40] [c008000010310250] > ext4_mount+0x28/0x50 [ext4] > [ 208.681520][T27684] [c000200361defc60] [c00000000053242c] > legacy_get_tree+0x4c/0xb0 > [ 208.681556][T27684] [c000200361defc90] [c0000000004c864c] > vfs_get_tree+0x4c/0x130 > [ 208.681593][T27684] [c000200361defd00] [c00000000050a1c8] > do_mount+0xa18/0xc50 > [ 208.681641][T27684] [c000200361defdd0] [c00000000050a9a8] > sys_mount+0x158/0x180 > [ 208.681679][T27684] [c000200361defe20] [c00000000000b3f8] > system_call+0x5c/0x68 > [ 208.681726][T27684] Instruction dump: > [ 208.681747][T27684] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX > XXXXXXXX XXXXXXXX > [ 208.681797][T27684] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX > XXXXXXXX XXXXXXXX > [ 208.681839][T27684] ---[ end trace 4e9e2bab7f1d4048 ]--- > [ 208.802259][T27684] > [ 209.802373][T27684] Kernel panic - not syncing: Fatal exception > > [ 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
