1514839b36
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:
|
||
|---|---|---|
| Documentation | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.