Re: [linux-next][mainline/master] [IPR] [Function could be = "__mutex_lock_slowpath(lock)"]OOPs kernel crash while performing IPR test

[Waiman Long <longman@redhat.com>]

On 8/27/23 04:26, Tasmiya Nalatwad wrote:
> Greetings,
>
> [linux-next][mainline/master] [IPR] [Function could be = 
> "__mutex_lock_slowpath(lock)"]OOPs kernel crash while performing IPR test
>
> --- Traces ---
>
> --- Traces ---
> [65818.211823] Kernel attempted to read user page (380) - exploit 
> attempt? (uid: 0)
> [65818.211836] BUG: Kernel NULL pointer dereference on read at 0x00000380
> [65818.211840] Faulting instruction address: 0xc000000000f5f2e4
> [65818.211844] Oops: Kernel access of bad area, sig: 11 [#1]
> [65818.211846] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=8192 NUMA pSeries
> [65818.211850] Modules linked in: rpadlpar_io rpaphp nfnetlink 
> xsk_diag bonding tls rfkill sunrpc ses enclosure scsi_transport_sas 
> vmx_crypto pseries_rng binfmt_misc ip_tables ext4 mbcache jbd2 
> dm_service_time sd_mod t10_pi crc64_rocksoft crc64 sg ibmvfc 
> scsi_transport_fc ibmveth ipr dm_multipath dm_mirror dm_region_hash 
> dm_log dm_mod fuse
> [65818.211879] CPU: 16 PID: 613 Comm: kworker/16:3 Kdump: loaded Not 
> tainted 6.5.0-rc7-next-20230824-auto #1
> [65818.211883] Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 
> 0xf000006 of:IBM,FW1030.30 (NH1030_062) hv:phyp pSeries
> [65818.211887] Workqueue: events sg_remove_sfp_usercontext [sg]
> [65818.211894] NIP:  c000000000f5f2e4 LR: c000000000f5f2d8 CTR: 
> c00000000032df70
> [65818.211897] REGS: c0000000081c7a10 TRAP: 0300   Not tainted 
> (6.5.0-rc7-next-20230824-auto)
> [65818.211900] MSR:  800000000280b033 
> <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 28000882  XER: 20040000
> [65818.211909] CFAR: c000000000f5b0a4 DAR: 0000000000000380 DSISR: 
> 40000000 IRQMASK: 0
> [65818.211909] GPR00: c000000000f5f2d8 c0000000081c7cb0 
> c000000001451300 0000000000000000
> [65818.211909] GPR04: 00000000000000c0 00000000c0000000 
> c000000006c5a298 98a2c506000000c0
> [65818.211909] GPR08: c00000006408ab00 c0000000022a3515 
> 0000000000000000 c008000000327d60
> [65818.211909] GPR12: c00000000032df70 c000000c1bc93f00 
> c000000000197cc8 c000000008797500
> [65818.211909] GPR16: 0000000000000000 0000000000000000 
> 0000000000000000 c000000003071ab0
> [65818.211909] GPR20: c000000003494c05 c000000c11340040 
> 0000000000000000 c0000000b9bb4030
> [65818.211909] GPR24: c0000000b9bb4000 c00000005e8627c0 
> 0000000000000000 c000000c19b91e00
> [65818.211909] GPR28: c0000000b9bb5328 c00000005e8627c0 
> 0000000000000380 0000000000000380
> [65818.211946] NIP [c000000000f5f2e4] mutex_lock+0x34/0x90
> [65818.211953] LR [c000000000f5f2d8] mutex_lock+0x28/0x90
> [65818.211957] Call Trace:
> [65818.211959] [c0000000081c7cb0] [c000000000f5f2d8] 
> mutex_lock+0x28/0x90 (unreliable)
> [65818.211966] [c0000000081c7ce0] [c00000000032df9c] 
> blk_trace_remove+0x2c/0x80
> [65818.211971] [c0000000081c7d10] [c0080000003205fc] 
> sg_device_destroy+0x44/0x110 [sg]
> [65818.211976] [c0000000081c7d90] [c008000000322988] 
> sg_remove_sfp_usercontext+0x1d0/0x2c0 [sg]
> [65818.211981] [c0000000081c7e40] [c000000000188010] 
> process_scheduled_works+0x230/0x4f0
> [65818.211987] [c0000000081c7f10] [c00000000018b044] 
> worker_thread+0x1e4/0x500
> [65818.211992] [c0000000081c7f90] [c000000000197df8] kthread+0x138/0x140
> [65818.211996] [c0000000081c7fe0] [c00000000000df98] 
> start_kernel_thread+0x14/0x18 

The panic happens when a device is being removed. Maybe it is a 
use-after-free problem. The mutex lock itself seems to be in an area 
that is no longer accessible. It is not a problem in the locking code 
itself.

Cheers,
Longman