Commits
himanshu.madhani@cavium.com committed 1514839b366
scsi: qla2xxx: Fix NULL pointer crash due to active timer for ABTS
This patch fixes NULL pointer crash due to active timer running for abort
IOCB.
From crash dump analysis it was discoverd that get_next_timer_interrupt()
encountered a corrupted entry on the timer list.
#9 [ffff95e1f6f0fd40] page_fault at ffffffff914fe8f8
[exception RIP: get_next_timer_interrupt+440]
RIP: ffffffff90ea3088 RSP: ffff95e1f6f0fdf0 RFLAGS: 00010013
RAX: ffff95e1f6451028 RBX: 000218e2389e5f40 RCX: 00000001232ad600
RDX: 0000000000000001 RSI: ffff95e1f6f0fdf0 RDI: 0000000001232ad6
RBP: ffff95e1f6f0fe40 R8: ffff95e1f6451188 R9: 0000000000000001
R10: 0000000000000016 R11: 0000000000000016 R12: 00000001232ad5f6
R13: ffff95e1f6450000 R14: ffff95e1f6f0fdf8 R15: ffff95e1f6f0fe10
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
Looking at the assembly of get_next_timer_interrupt(), address came
from %r8 (ffff95e1f6451188) which is pointing to list_head with single
entry at ffff95e5ff621178.
0xffffffff90ea307a <get_next_timer_interrupt+426>: mov (%r8),%rdx
0xffffffff90ea307d <get_next_timer_interrupt+429>: cmp %r8,%rdx
0xffffffff90ea3080 <get_next_timer_interrupt+432>: je 0xffffffff90ea30a7 <get_next_timer_interrupt+471>
0xffffffff90ea3082 <get_next_timer_interrupt+434>: nopw 0x0(%rax,%rax,1)
0xffffffff90ea3088 <get_next_timer_interrupt+440>: testb $0x1,0x18(%rdx)
crash> rd ffff95e1f6451188 10
ffff95e1f6451188: ffff95e5ff621178 ffff95e5ff621178 x.b.....x.b.....
ffff95e1f6451198: ffff95e1f6451198 ffff95e1f6451198 ..E.......E.....
ffff95e1f64511a8: ffff95e1f64511a8 ffff95e1f64511a8 ..E.......E.....
ffff95e1f64511b8: ffff95e77cf509a0 ffff95e77cf509a0 ...|.......|....
ffff95e1f64511c8: ffff95e1f64511c8 ffff95e1f64511c8 ..E.......E.....
crash> rd ffff95e5ff621178 10
ffff95e5ff621178: 0000000000000001 ffff95e15936aa00 ..........6Y....
ffff95e5ff621188: 0000000000000000 00000000ffffffff ................
ffff95e5ff621198: 00000000000000a0 0000000000000010 ................
ffff95e5ff6211a8: ffff95e5ff621198 000000000000000c ..b.............
ffff95e5ff6211b8: 00000f5800000000 ffff95e751f8d720 ....X... ..Q....
ffff95e5ff621178 belongs to freed mempool object at ffff95e5ff621080.
CACHE NAME OBJSIZE ALLOCATED TOTAL SLABS SSIZE
ffff95dc7fd74d00 mnt_cache 384 19785 24948 594 16k
SLAB MEMORY NODE TOTAL ALLOCATED FREE
ffffdc5dabfd8800 ffff95e5ff620000 1 42 29 13
FREE / [ALLOCATED]
ffff95e5ff621080 (cpu 6 cache)
Examining the contents of that memory reveals a pointer to a constant string
in the driver, "abort\0", which is set by qla24xx_async_abort_cmd().
crash> rd ffffffffc059277c 20
ffffffffc059277c: 6e490074726f6261 0074707572726574 abort.Interrupt.
ffffffffc059278c: 00676e696c6c6f50 6920726576697244 Polling.Driver i
ffffffffc059279c: 646f6d207325206e 6974736554000a65 n %s mode..Testi
ffffffffc05927ac: 636976656420676e 786c252074612065 ng device at %lx
ffffffffc05927bc: 6b63656843000a2e 646f727020676e69 ...Checking prod
ffffffffc05927cc: 6f20444920746375 0a2e706968632066 uct ID of chip..
ffffffffc05927dc: 5120646e756f4600 204130303232414c .Found QLA2200A
ffffffffc05927ec: 43000a2e70696843 20676e696b636568 Chip...Checking
ffffffffc05927fc: 65786f626c69616d 6c636e69000a2e73 mailboxes...incl
ffffffffc059280c: 756e696c2f656475 616d2d616d642f78 ude/linux/dma-ma
crash> struct -ox srb_iocb
struct srb_iocb {
union {
struct {...} logio;
struct {...} els_logo;
struct {...} tmf;
struct {...} fxiocb;
struct {...} abt;
struct ct_arg ctarg;
struct {...} mbx;
struct {...} nack;
[0x0 ] } u;
[0xb8] struct timer_list timer;
[0x108] void (*timeout)(void *);
}
SIZE: 0x110
crash> ! bc
ibase=16
obase=10
B8+40
F8
The object is a srb_t, and at offset 0xf8 within that structure
(i.e. ffff95e5ff621080 + f8 -> ffff95e5ff621178) is a struct timer_list.
Cc: <stable@vger.kernel.org> #4.4+
Fixes: 4440e46d5db7 ("[SCSI] qla2xxx: Add IOCB Abort command asynchronous handling.")
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>