KASAN: out-of-bounds Read in unwind_next_frame

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: f6e27dbb Linux 4.14.146
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=134613d5600000
kernel config: https://syzkaller.appspot.com/x/.config?x=cb75afefe94a0801
dashboard link: https://syzkaller.appspot.com/bug?extid=e429b520902a478095d0
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e429b5...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: out-of-bounds in unwind_next_frame.part.0+0x76d/0x8b0
arch/x86/kernel/unwind_frame.c:327
Read of size 8 at addr ffff88806d1d7e68 by task syz-executor.4/879

CPU: 0 PID: 879 Comm: syz-executor.4 Not tainted 4.14.146 #0
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+0x138/0x197 lib/dump_stack.c:53
print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351 [inline]
kasan_report mm/kasan/report.c:409 [inline]
kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
unwind_next_frame.part.0+0x76d/0x8b0 arch/x86/kernel/unwind_frame.c:327
unwind_next_frame+0x3b/0x50 arch/x86/kernel/unwind_frame.c:287
__save_stack_trace+0x6b/0xd0 arch/x86/kernel/stacktrace.c:44
save_stack_trace_tsk arch/x86/kernel/stacktrace.c:73 [inline]
save_stack_trace_tsk+0x3e/0x50 arch/x86/kernel/stacktrace.c:68
proc_pid_stack+0x174/0x250 fs/proc/base.c:459
proc_single_show+0xf0/0x160 fs/proc/base.c:761
seq_read+0x51a/0x1280 fs/seq_file.c:237
do_loop_readv_writev fs/read_write.c:695 [inline]
do_loop_readv_writev fs/read_write.c:682 [inline]
do_iter_read+0x3e2/0x5b0 fs/read_write.c:919
vfs_readv+0xd3/0x130 fs/read_write.c:981
do_preadv+0x15d/0x200 fs/read_write.c:1065
SYSC_preadv fs/read_write.c:1115 [inline]
SyS_preadv+0x31/0x40 fs/read_write.c:1110
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459a29
RSP: 002b:00007f2edbca6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459a29
RDX: 10000000000002a1 RSI: 0000000020000480 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2edbca76d4
R13: 00000000004c6d3d R14: 00000000004dc0b8 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea0001b475c0 count:0 mapcount:0 mapping: (null) index:0x0
flags: 0x1fffc0000000000()
raw: 01fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88806d1d7d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88806d1d7d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff88806d1d7e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
ffff88806d1d7e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88806d1d7f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: e1f7d50a Linux 4.14.160
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10b74085e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=46599517442ad9fb

dashboard link: https://syzkaller.appspot.com/bug?extid=e429b520902a478095d0
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=128d99c1e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16d31ac6e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e429b5...@syzkaller.appspotmail.com

==================================================================

BUG: KASAN: out-of-bounds in unwind_next_frame.part.0+0x627/0x8b0
arch/x86/kernel/unwind_frame.c:291
Read of size 8 at addr ffff8880988df9f0 by task syz-executor280/10550

CPU: 0 PID: 10550 Comm: syz-executor280 Not tainted 4.14.160-syzkaller #0

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+0x142/0x197 lib/dump_stack.c:58

print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351 [inline]
kasan_report mm/kasan/report.c:409 [inline]
kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430

unwind_next_frame.part.0+0x627/0x8b0 arch/x86/kernel/unwind_frame.c:291

unwind_next_frame+0x3b/0x50 arch/x86/kernel/unwind_frame.c:287
__save_stack_trace+0x6b/0xd0 arch/x86/kernel/stacktrace.c:44
save_stack_trace_tsk arch/x86/kernel/stacktrace.c:73 [inline]
save_stack_trace_tsk+0x3e/0x50 arch/x86/kernel/stacktrace.c:68
proc_pid_stack+0x174/0x250 fs/proc/base.c:459
proc_single_show+0xf0/0x160 fs/proc/base.c:761
seq_read+0x51a/0x1280 fs/seq_file.c:237
do_loop_readv_writev fs/read_write.c:695 [inline]
do_loop_readv_writev fs/read_write.c:682 [inline]
do_iter_read+0x3e2/0x5b0 fs/read_write.c:919
vfs_readv+0xd3/0x130 fs/read_write.c:981
do_preadv+0x15d/0x200 fs/read_write.c:1065
SYSC_preadv fs/read_write.c:1115 [inline]
SyS_preadv+0x31/0x40 fs/read_write.c:1110
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7

RIP: 0033:0x448c19
RSP: 002b:00007f101edeed08 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00000000006dec68 RCX: 0000000000448c19
RDX: 000000000000022a RSI: 00000000200017c0 RDI: 0000000000000004
RBP: 00000000006dec60 R08: 65732f636f72702f R09: 65732f636f72702f
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dec6c
R13: 00007f101edeed10 R14: 00007f101edeed10 R15: 0000000030626669

The buggy address belongs to the page:

page:ffffea00026237c0 count:0 mapcount:0 mapping: (null) index:0x0
flags: 0xfffe0000000000()
raw: 00fffe0000000000 0000000000000000 0000000000000000 00000000ffffffff

raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff8880988df880: 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 f3 f3 00
ffff8880988df900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8880988df980: f1 f1 f1 f1 00 00 00 f2 f2 f2 00 00 00 00 00 00
^
ffff8880988dfa00: 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00 00 00 00
ffff8880988dfa80: 00 00 00 00 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00
==================================================================