4.4-stable review patch. If anyone has any objections, please let me know.
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From: himanshu.madhani@cavium.com himanshu.madhani@cavium.com
commit 1514839b366417934e2f1328edb50ed1e8a719f5 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/scsi/qla2xxx/qla_init.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/scsi/qla2xxx/qla_init.c +++ b/drivers/scsi/qla2xxx/qla_init.c @@ -365,6 +365,7 @@ qla24xx_abort_sp_done(void *data, void * srb_t *sp = (srb_t *)ptr; struct srb_iocb *abt = &sp->u.iocb_cmd;
+ del_timer(&sp->u.iocb_cmd.timer); complete(&abt->u.abt.comp); }