KASAN: global-out-of-bounds Read in show_timer

[syzbot]

Hello,

syzkaller hit the following crash on
4131d5166185d0d75b5f1d4bf362a9e0bac05598
git://git.cmpxchg.org/linux-mmots.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.

Unfortunately, I don't have any reproducer for this bug yet.


device gre0 entered promiscuous mode
==================================================================
BUG: KASAN: global-out-of-bounds in show_timer+0x278/0x2b0
fs/proc/base.c:2303
Read of size 8 at addr ffffffff85343838 by task syz-executor2/9292

CPU: 0 PID: 9292 Comm: syz-executor2 Not tainted 4.15.0-rc1-mm1+ #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:53
print_address_description+0x178/0x250 mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351 [inline]
kasan_report+0x25b/0x340 mm/kasan/report.c:409
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
show_timer+0x278/0x2b0 fs/proc/base.c:2303
seq_read+0x385/0x13d0 fs/seq_file.c:234
QAT: Invalid ioctl
do_loop_readv_writev fs/read_write.c:673 [inline]
do_iter_read+0x3db/0x5b0 fs/read_write.c:897
vfs_readv+0x121/0x1c0 fs/read_write.c:959
do_preadv+0x11b/0x1a0 fs/read_write.c:1043
SYSC_preadv fs/read_write.c:1093 [inline]
SyS_preadv+0x30/0x40 fs/read_write.c:1088
entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x4529d9
RSP: 002b:00007f2c4bcddc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 00000000004529d9
RDX: 0000000000000001 RSI: 0000000020b39000 RDI: 0000000000000013
RBP: 00000000000005f4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f5f80
R13: 00000000ffffffff R14: 00007f2c4bcde6d4 R15: 0000000000000000

The buggy address belongs to the variable:
nstr.44309+0x18/0x40

Memory state around the buggy address:
ffffffff85343700: fa fa fa fa 00 06 fa fa fa fa fa fa 07 fa fa fa
ffffffff85343780: fa fa fa fa 05 fa fa fa fa fa fa fa 07 fa fa fa
> ffffffff85343800: fa fa fa fa 00 00 00 fa fa fa fa fa 00 fa fa fa
^
ffffffff85343880: fa fa fa fa 07 fa fa fa fa fa fa fa 00 00 00 00
ffffffff85343900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 9292 Comm: syz-executor2 Tainted: G B
4.15.0-rc1-mm1+ #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:53
panic+0x1e4/0x41c kernel/panic.c:183
kasan_end_report+0x50/0x50 mm/kasan/report.c:176
kasan_report_error mm/kasan/report.c:356 [inline]
kasan_report+0x144/0x340 mm/kasan/report.c:409
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
show_timer+0x278/0x2b0 fs/proc/base.c:2303
seq_read+0x385/0x13d0 fs/seq_file.c:234
do_loop_readv_writev fs/read_write.c:673 [inline]
do_iter_read+0x3db/0x5b0 fs/read_write.c:897
vfs_readv+0x121/0x1c0 fs/read_write.c:959
do_preadv+0x11b/0x1a0 fs/read_write.c:1043
SYSC_preadv fs/read_write.c:1093 [inline]
SyS_preadv+0x30/0x40 fs/read_write.c:1088
entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x4529d9
RSP: 002b:00007f2c4bcddc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 00000000004529d9
RDX: 0000000000000001 RSI: 0000000020b39000 RDI: 0000000000000013
RBP: 00000000000005f4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f5f80
R13: 00000000ffffffff R14: 00007f2c4bcde6d4 R15: 0000000000000000
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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See https://goo.gl/tpsmEJ for details.
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[syzbot]

syzkaller has found reproducer for the following crash on
fb20eb9d798d2f4c1a75b7fe981d72dfa8d7270d
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master

compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.

C reproducer is attached
syzkaller reproducer is attached. See https://goo.gl/kgGztJ
for information about syzkaller reproducers

==================================================================
BUG: KASAN: global-out-of-bounds in show_timer+0x278/0x2b0
fs/proc/base.c:2303

Read of size 8 at addr ffffffff85343578 by task syzkaller289632/3091

CPU: 1 PID: 3091 Comm: syzkaller289632 Not tainted
4.15.0-rc1-next-20171201+ #57

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:53
print_address_description+0x178/0x250 mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351 [inline]
kasan_report+0x25b/0x340 mm/kasan/report.c:409
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
show_timer+0x278/0x2b0 fs/proc/base.c:2303
seq_read+0x385/0x13d0 fs/seq_file.c:234

do_loop_readv_writev fs/read_write.c:673 [inline]
do_iter_read+0x3db/0x5b0 fs/read_write.c:897
vfs_readv+0x121/0x1c0 fs/read_write.c:959
do_preadv+0x11b/0x1a0 fs/read_write.c:1043
SYSC_preadv fs/read_write.c:1093 [inline]
SyS_preadv+0x30/0x40 fs/read_write.c:1088
entry_SYSCALL_64_fastpath+0x1f/0x96

RIP: 0033:0x440209
RSP: 002b:00007fff70ef6758 EFLAGS: 00000217 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007fff70ef6760 RCX: 0000000000440209
RDX: 0000000000000008 RSI: 0000000020508000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 65732f636f72702f R09: 65732f636f72702f
R10: 0000000000000000 R11: 0000000000000217 R12: 0000000000401ad0
R13: 0000000000401b60 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the variable:

nstr.44312+0x18/0x40

Memory state around the buggy address:

ffffffff85343400: fa fa fa fa 00 00 00 fa fa fa fa fa 00 06 fa fa
ffffffff85343480: fa fa fa fa 07 fa fa fa fa fa fa fa 05 fa fa fa
> ffffffff85343500: fa fa fa fa 07 fa fa fa fa fa fa fa 00 00 00 fa
^
ffffffff85343580: fa fa fa fa 00 fa fa fa fa fa fa fa 07 fa fa fa
ffffffff85343600: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 00

==================================================================
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 3091 Comm: syzkaller289632 Tainted: G B
4.15.0-rc1-next-20171201+ #57

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:53
panic+0x1e4/0x41c kernel/panic.c:183
kasan_end_report+0x50/0x50 mm/kasan/report.c:176
kasan_report_error mm/kasan/report.c:356 [inline]
kasan_report+0x144/0x340 mm/kasan/report.c:409
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
show_timer+0x278/0x2b0 fs/proc/base.c:2303
seq_read+0x385/0x13d0 fs/seq_file.c:234
do_loop_readv_writev fs/read_write.c:673 [inline]
do_iter_read+0x3db/0x5b0 fs/read_write.c:897
vfs_readv+0x121/0x1c0 fs/read_write.c:959
do_preadv+0x11b/0x1a0 fs/read_write.c:1043
SYSC_preadv fs/read_write.c:1093 [inline]
SyS_preadv+0x30/0x40 fs/read_write.c:1088
entry_SYSCALL_64_fastpath+0x1f/0x96

RIP: 0033:0x440209
RSP: 002b:00007fff70ef6758 EFLAGS: 00000217 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007fff70ef6760 RCX: 0000000000440209
RDX: 0000000000000008 RSI: 0000000020508000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 65732f636f72702f R09: 65732f636f72702f
R10: 0000000000000000 R11: 0000000000000217 R12: 0000000000401ad0
R13: 0000000000401b60 R14: 0000000000000000 R15: 0000000000000000

[Eric Biggers]

On Fri, Dec 01, 2017 at 04:53:01AM -0800, syzbot wrote:
> This bug is generated by a dumb bot. It may contain errors.
> See https://goo.gl/tpsmEJ for details.
> Direct all questions to syzk...@googlegroups.com.
> Please credit me with: Reported-by: syzbot <syzk...@googlegroups.com>
>
> syzbot will keep track of this bug report.
> Once a fix for this bug is committed, please reply to this email with:
> #syz fix: exact-commit-title
> To mark this as a duplicate of another syzbot report, please reply with:
> #syz dup: exact-subject-of-another-report
> If it's a one-off invalid bug report, please reply with:
> #syz invalid
> Note: if the crash happens again, it will cause creation of a new
> bug report.
> Note: all commands must start from beginning of the line in the email body.

#syz dup: general protection fault in show_timer