syzbot


KASAN: use-after-free Read in __schedule

Status: auto-closed as invalid on 2021/06/29 13:25
Reported-by: syzbot+85ca27c917d81cd1287d@syzkaller.appspotmail.com
First crash: 1090d, last: 1090d
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-54 KASAN: use-after-free Read in __schedule 3 1426d 1453d 0/2 auto-closed as invalid on 2020/07/28 03:17
upstream KASAN: use-after-free Read in __schedule kvm C 145 2255d 2257d 4/26 fixed on 2018/02/14 17:41
linux-4.19 KASAN: use-after-free Read in __schedule (2) 1 767d 767d 0/1 auto-closed as invalid on 2022/05/18 22:28
upstream KASAN: use-after-free Read in __schedule (2) kvm C done 961 1813d 2032d 13/26 fixed on 2019/11/20 22:01
upstream KMSAN: uninit-value in __schedule (4) sctp reiserfs C error 4 176d 172d 0/26 auto-obsoleted due to no activity on 2023/12/10 17:35
android-54 BUG: unable to handle kernel paging request in __schedule C 12 1094d 1251d 0/2 auto-obsoleted due to no activity on 2023/04/17 21:57
upstream KMSAN: uninit-value in __schedule (3) trace net 2 373d 377d 0/26 auto-obsoleted due to no activity on 2023/05/17 02:32
upstream KMSAN: uninit-value in __schedule (2) kernel 1 547d 547d 0/26 auto-obsoleted due to no activity on 2022/11/24 18:35

Sample crash report:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
==================================================================
BUG: KASAN: use-after-free in schedule_debug kernel/sched/core.c:3329 [inline]
BUG: KASAN: use-after-free in __schedule+0x1ae3/0x2040 kernel/sched/core.c:3439
Read of size 8 at addr ffff8880465d0000 by task syz-executor.5/16762

CPU: 1 PID: 16762 Comm: syz-executor.5 Not tainted 4.19.177-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
 schedule_debug kernel/sched/core.c:3329 [inline]
 __schedule+0x1ae3/0x2040 kernel/sched/core.c:3439
 preempt_schedule_notrace+0x92/0x110 kernel/sched/core.c:3715
 ___preempt_schedule_notrace+0x16/0x2e
 rcu_is_watching+0x96/0xc0 kernel/rcu/tree.c:1026
 rcu_read_unlock include/linux/rcupdate.h:677 [inline]
 ext4_get_group_desc+0x2de/0x4e0 fs/ext4/balloc.c:284
 recently_deleted fs/ext4/ialloc.c:681 [inline]
 find_inode_bit+0x1a0/0x520 fs/ext4/ialloc.c:725
 __ext4_new_inode+0x160c/0x5a20 fs/ext4/ialloc.c:917
 ext4_symlink+0x3f5/0xc00 fs/ext4/namei.c:3177
 vfs_symlink+0x453/0x6c0 fs/namei.c:4129
 do_symlinkat+0x258/0x2c0 fs/namei.c:4156
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x465807
Code: 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 58 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd986f7228 EFLAGS: 00000206 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000465807
RDX: 00007ffd986f7317 RSI: 00000000004bcdbd RDI: 00007ffd986f7300
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffd986f70c0
R10: 00007ffd986f6f77 R11: 0000000000000206 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000001 R15: 00007ffd986f7300

The buggy address belongs to the page:
page:ffffea0001197400 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfff00000000000()
raw: 00fff00000000000 ffffea000118f248 ffff8880ba12e9f8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880465cff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880465cff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880465d0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8880465d0080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880465d0100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/03/01 13:24 linux-4.19.y 2d19be4653f5 4c37c133 .config console log report info ci2-linux-4-19 KASAN: use-after-free Read in __schedule
* Struck through repros no longer work on HEAD.