[LU-18558] BUG: unable to handle kernel NULL pointer dereference in osd_iit_iget()

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.17.0
• Severity: 3
• Assignee: Alex Zhuravlev
• Reporter: Alex Zhuravlev

Description

[  904.017810] Lustre: DEBUG MARKER: == sanity-lfsck test 18a: Find out orphan OST-object and repair it (1) ========================================================== 11:03:05 (1734174185)
.......
[  906.558589] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[  906.558716] PGD 0 P4D 0 
[  906.558753] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[  906.558817] CPU: 0 PID: 47520 Comm: lfsck Tainted: G        W  O     --------- -  - 4.18.0 #11
[  906.558925] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-1.fc39 04/01/2014
[  906.559032] RIP: 0010:osd_iit_iget+0x235/0x4e0 [osd_ldiskfs]
[  906.559141] Code: 8b 36 48 83 fe 01 74 1b 48 83 fe 0a 74 15 48 b8 fd ff ff ff fd ff ff ff 48 01 f0 48 a9 fd ff ff ff 75 2e 48 8b bb 70 ab 00 00 <48> 3b 37 0f 84 79 02 00 00 31 d2 eb 13 48 63 c2 48 c1 e0 04 48 01
[  906.559359] RSP: 0018:ffff976c0c013c40 EFLAGS: 00010246
[  906.559424] RAX: 0000000000000002 RBX: ffff976c080c0000 RCX: 0000000000000003
[  906.559516] RDX: 0000000080000001 RSI: 0000000200000005 RDI: 0000000000000000
[  906.559607] RBP: ffff976c1ca822d0 R08: 0000000000000000 R09: 0000000000000061
[  906.559699] R10: ffffffffc0d03e40 R11: 0000000000000000 R12: 0000000000004e5d
[  906.559791] R13: 0000000000000002 R14: ffff976c4144f288 R15: 0000000000004e5d
[  906.559883] FS:  0000000000000000(0000) GS:ffff976c8b000000(0000) knlGS:0000000000000000
[  906.559973] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  906.560051] CR2: 0000000000000000 CR3: 000000011e011005 CR4: 0000000000370eb0
[  906.560144] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  906.560241] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  906.560332] Call Trace:
[  906.560367]  osd_preload_next+0x85/0x90 [osd_ldiskfs]
[  906.560455]  osd_inode_iteration+0x360/0xbc0 [osd_ldiskfs]
[  906.560539]  ? osd_iit_next.part.1+0x110/0x110 [osd_ldiskfs]
[  906.560636]  ? osd_obj_spec_lookup+0x270/0x270 [osd_ldiskfs]
[  906.560732]  ? rcu_read_lock_held_common+0x9/0x30
[  906.560799]  ? rcu_read_lock_sched_held+0xe/0x60
[  906.560862]  ? lock_acquire+0x1ac/0x3f0
[  906.560911]  ? rcu_read_lock_held_common+0x9/0x30
[  906.560974]  osd_otable_it_next+0x19c/0x610 [osd_ldiskfs]
[  906.561057]  ? _raw_read_unlock+0x24/0x40
[  906.561109]  ? fld_cache_lookup+0x115/0x1c0 [fld]
[  906.561182]  lfsck_master_engine+0xfd6/0x35a0 [lfsck]
[  906.561275]  ? trace_hardirqs_on+0x1c/0xe0
[  906.561326]  ? rcu_read_lock_held_common+0x9/0x30
[  906.561390]  ? rcu_read_lock_sched_held+0xe/0x60
[  906.561456]  ? wait_woken+0x80/0x80
[  906.561507]  ? lfsck_open_dir+0x3b0/0x3b0 [lfsck]
[  906.561586]  kthread+0x16e/0x1a0
[  906.561655]  ? set_kthread_struct+0x40/0x40

this is os_ls_fids=NULL:

/home/lustre/master-mine/lustre/osd-ldiskfs/osd_scrub.c:
689				if (scrub->os_ls_fids[index].f_seq == fid->f_seq)
   0xffffffffc0e2c29e <+558>:	mov    0xab70(%rbx),%rdi
   0xffffffffc0e2c2a5 <+565>:	cmp    (%rdi),%rsi
   0xffffffffc0e2c2a8 <+568>:	je     0xffffffffc0e2c527 <osd_iit_iget+1207>
   0xffffffffc0e2c2ae <+574>:	xor    %edx,%edx
   0xffffffffc0e2c2b0 <+576>:	jmp    0xffffffffc0e2c2c5 <osd_iit_iget+597>

....
crash> p/x 0xa708+0x468
$5 = 0xab70

...
crash> p *(struct osd_device *)0xffff976c080c0000
      os_ls_fids = 0x0,