[linux-next-20250214]Kernel OOPs while running LTP test readahead02 on 6.14.0-rc2-next-20250214

[NeilBrown]

Thanks for the report. I've posted a revised version of that patch which
adds the missing error check on the result of ->lookup.

NeilBrown


On Mon, 17 Feb 2025, Venkat Rao Bagalkote wrote:
> Greetings!!!
> 
> 
> I am observing kernel oops on IBM Power system while running LTP test 
> readahead02 on 6.14.0-rc2-next-20250214 kernel.
> 
> 
> By Reverting the below patch, issue is not seen.
> 
>      Revert "VFS: add common error checks to lookup_one_qstr_excl()"
> 
>      This reverts commit 22d9d5e93d0eaf7e8662602713b24e9b6171759f
> 
> 
> Please help to fix this issue and request to add the below tag.
> 
> Reported-by: Venkat Rao Bagalkote <venkat88 at linux.vnet.ibm.com>
> 
> 
> Traces:
> 
> [ 2154.427377] BUG: Unable to handle kernel data access at 
> 0xffffffffffffffdc
> [ 2154.427390] Faulting instruction address: 0xc00000000062a560
> [ 2154.427397] Oops: Kernel access of bad area, sig: 11 [#1]
> [ 2154.427402] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=8192 NUMA pSeries
> [ 2154.427410] Modules linked in: dns_resolver(E) tun(E) brd(E) 
> overlay(E) exfat(E) vfat(E) fat(E) loop(E) sctp(E) ip6_udp_tunnel(E) 
> udp_tunnel(E) ext4(E) mbcache(E) jbd2(E) dm_mod(E) bonding(E) tls(E) 
> nft_fib_inet(E) nft_fib_ipv4(E) nft_fib_ipv6(E) nft_fib(E) 
> nft_reject_inet(E) nf_reject_ipv4(E) nf_reject_ipv6(E) nft_reject(E) 
> nft_ct(E) nft_chain_nat(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) 
> nf_defrag_ipv4(E) ip_set(E) rfkill(E) nf_tables(E) nfnetlink(E) hvcs(E) 
> pseries_rng(E) hvcserver(E) vmx_crypto(E) drm(E) 
> drm_panel_orientation_quirks(E) xfs(E) sr_mod(E) cdrom(E) sd_mod(E) 
> lpfc(E) sg(E) nvmet_fc(E) nvmet(E) ibmvscsi(E) scsi_transport_srp(E) 
> ibmveth(E) nvme_fc(E) nvme_fabrics(E) bnx2x(E) nvme_core(E) be2net(E) 
> mdio(E) scsi_transport_fc(E) fuse(E) [last unloaded: hwpoison_inject(E)]
> [ 2154.427514] CPU: 30 UID: 0 PID: 784383 Comm: rename10 Tainted: 
> G           OE      6.14.0-rc2-next-20250214 #1
> [ 2154.427524] Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
> [ 2154.427528] Hardware name: IBM,8375-42A POWER9 (architected) 0x4e0202 
> 0xf000005 of:IBM,FW950.80 (VL950_131) hv:phyp pSeries
> [ 2154.427534] NIP:  c00000000062a560 LR: c00000000062a618 CTR: 
> c00800000dbb4a10
> [ 2154.427540] REGS: c00000054af579b0 TRAP: 0380   Tainted: G           
> OE       (6.14.0-rc2-next-20250214)
> [ 2154.427547] MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 
> 2802222f  XER: 20040000
> [ 2154.427561] CFAR: c00000000062a61c IRQMASK: 0
> [ 2154.427561] GPR00: c00000000062a618 c00000054af57c50 c000000001677600 
> 0000000000000000
> [ 2154.427561] GPR04: c0000003c48560b0 00000000000a0000 0000000000000000 
> c000000002cfaa88
> [ 2154.427561] GPR08: 0000000000002710 0000000000000000 0000000000000000 
> 6161616161616161
> [ 2154.427561] GPR12: c00800000dbb4a10 c00000000f75af00 0000000000000000 
> 0000000000000000
> [ 2154.427561] GPR16: 0000000000000000 00000000000a0000 0000000000000000 
> 0000000000000000
> [ 2154.427561] GPR20: 0000000000100000 0000000000000002 00000000000a0000 
> 0000000000000000
> [ 2154.427561] GPR24: fffffffffffff000 ffffffffffffff9c ffffffffffffff9c 
> c0000005488e1c28
> [ 2154.427561] GPR28: c00000054af57d08 c0000005484eae00 00000000000a0000 
> ffffffffffffffdc
> [ 2154.427627] NIP [c00000000062a560] lookup_one_qstr_excl+0x50/0x148
> [ 2154.427639] LR [c00000000062a618] lookup_one_qstr_excl+0x108/0x148
> [ 2154.427646] Call Trace:
> [ 2154.427649] [c00000054af57c50] [c00000000062a618] 
> lookup_one_qstr_excl+0x108/0x148 (unreliable)
> [ 2154.427659] [c00000054af57ca0] [c00000000063510c] 
> do_renameat2+0x360/0x63c
> [ 2154.427666] [c00000054af57de0] [c000000000635570] sys_rename+0x5c/0x74
> [ 2154.427672] [c00000054af57e10] [c000000000033638] 
> system_call_exception+0x138/0x330
> [ 2154.427681] [c00000054af57e50] [c00000000000d05c] 
> system_call_vectored_common+0x15c/0x2ec
> [ 2154.427690] --- interrupt: 3000 at 0x7fffa1580804
> [ 2154.427697] NIP:  00007fffa1580804 LR: 00007fffa1580804 CTR: 
> 0000000000000000
> [ 2154.427702] REGS: c00000054af57e80 TRAP: 3000   Tainted: G           
> OE       (6.14.0-rc2-next-20250214)
> [ 2154.427708] MSR:  800000000280f033 
> <SF,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE>  CR: 44002228  XER: 00000000
> [ 2154.427725] IRQMASK: 0
> [ 2154.427725] GPR00: 0000000000000026 00007ffff0fb00d0 00007fffa1757200 
> 000000001002df18
> [ 2154.427725] GPR04: 0000000010051698 0000000000000047 0000000000000000 
> 0000000000000000
> [ 2154.427725] GPR08: 0000000010012b3c 0000000000000000 0000000000000000 
> 0000000000000000
> [ 2154.427725] GPR12: 0000000000000000 00007fffa181a560 0000000000000000 
> 0000000010032300
> [ 2154.427725] GPR16: 0000000010032a70 0000000010033100 0000000010033104 
> 0000000010032a98
> [ 2154.427725] GPR20: 00000000100328c8 0000000010032f70 0000000010031a00 
> 0000000000000000
> [ 2154.427725] GPR24: 0000000010052830 0000000010053cac 0000000010054544 
> 0000000010050690
> [ 2154.427725] GPR28: 0000000010053cb0 0000000000000000 000000001002df48 
> 00007fffa1813570
> [ 2154.427786] NIP [00007fffa1580804] 0x7fffa1580804
> [ 2154.427790] LR [00007fffa1580804] 0x7fffa1580804
> [ 2154.427794] --- interrupt: 3000
> [ 2154.427798] Code: fbc1fff0 fbe1fff8 7c9d2378 7c7c1b78 7cbe2b78 
> f8010010 f821ffb1 f8410018 4bfffee9 eb7d0030 7c7f1b79 41820064 
> <813f0000> 75290038 40820038 77de0002
> [ 2154.427820] ---[ end trace 0000000000000000 ]---
> [ 2154.591618] pstore: backend (nvram) writing error (-1)
> 
> 
> Regards,
> 
> Venkat.
> 
>