syzbot


KASAN: use-after-free Read in release_tty

Status: auto-closed as invalid on 2020/07/07 21:36
Reported-by: syzbot+364514747b351532772d@syzkaller.appspotmail.com
First crash: 842d, last: 842d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: use-after-free Read in release_tty 1 847d 847d 0/1 auto-closed as invalid on 2020/07/02 01:53

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline]
BUG: KASAN: use-after-free in atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline]
BUG: KASAN: use-after-free in atomic_long_read include/asm-generic/atomic-long.h:45 [inline]
BUG: KASAN: use-after-free in work_is_canceling kernel/workqueue.c:755 [inline]
BUG: KASAN: use-after-free in __cancel_work_timer+0x454/0x460 kernel/workqueue.c:2947
Read of size 8 at addr ffff888053b10588 by task syz-executor.2/24303

CPU: 0 PID: 24303 Comm: syz-executor.2 Not tainted 4.14.172-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+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 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+0xa9/0x2ae mm/kasan/report.c:393
 __read_once_size include/linux/compiler.h:183 [inline]
 atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline]
 atomic_long_read include/asm-generic/atomic-long.h:45 [inline]
 work_is_canceling kernel/workqueue.c:755 [inline]
 __cancel_work_timer+0x454/0x460 kernel/workqueue.c:2947
 release_tty+0x3e1/0x7a0 drivers/tty/tty_io.c:1507
 tty_release_struct+0x37/0x50 drivers/tty/tty_io.c:1616
 tty_release+0xaa6/0xd60 drivers/tty/tty_io.c:1776
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1d6/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x416041
RSP: 002b:00007ffeab4600b0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000416041
RDX: 0000001b2c820000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00000000f6c41bb6 R09: 00000000f6c41bba
R10: 00007ffeab460190 R11: 0000000000000293 R12: 000000000076bfc0
R13: 00000000007701d0 R14: 0000000000073b1e R15: 000000000076bfcc

Allocated by task 24306:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
 kmem_cache_alloc_trace+0x14d/0x7b0 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 vc_allocate drivers/tty/vt/vt.c:772 [inline]
 vc_allocate+0x142/0x550 drivers/tty/vt/vt.c:753
 con_install+0x4f/0x3e0 drivers/tty/vt/vt.c:2881
 tty_driver_install_tty drivers/tty/tty_io.c:1225 [inline]
 tty_init_dev drivers/tty/tty_io.c:1338 [inline]
 tty_init_dev+0xe1/0x3a0 drivers/tty/tty_io.c:1315
 tty_open_by_driver drivers/tty/tty_io.c:1973 [inline]
 tty_open+0x410/0x9c0 drivers/tty/tty_io.c:2021
 chrdev_open+0x1fc/0x540 fs/char_dev.c:423
 do_dentry_open+0x732/0xe90 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:891
 do_last fs/namei.c:3428 [inline]
 path_openat+0x8ca/0x3c50 fs/namei.c:3569
 do_filp_open+0x18e/0x250 fs/namei.c:3603
 do_sys_open+0x29d/0x3f0 fs/open.c:1084
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 24305:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 vt_disallocate_all+0x25c/0x340 drivers/tty/vt/vt_ioctl.c:323
 vt_ioctl+0x6e3/0x1f00 drivers/tty/vt/vt_ioctl.c:816
 tty_ioctl+0x6c5/0x1220 drivers/tty/tty_io.c:2661
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff888053b10580
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 8 bytes inside of
 2048-byte region [ffff888053b10580, ffff888053b10d80)
The buggy address belongs to the page:
page:ffffea00014ec400 count:1 mapcount:0 mapping:ffff888053b10580 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff888053b10580 0000000000000000 0000000100000003
raw: ffffea000145a720 ffffea0002831620 ffff88812fe56c40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888053b10480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888053b10500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888053b10580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888053b10600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888053b10680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2020/03/09 21:35 linux-4.14.y 78d697fc93f9 35f53e45 .config log report