syzbot


KASAN: use-after-free Read in wait_for_completion

Status: fixed on 2019/02/21 08:43
Subsystems: rdma
[Documentation on labels]
Reported-by: syzbot+f25db12f1fd508824eac@syzkaller.appspotmail.com
Fix commit: 5fe23f262e05 ucma: fix a use-after-free in ucma_resolve_ip()
First crash: 2010d, last: 2010d
Discussions (1)
Title Replies (including bot) Last reply
KASAN: use-after-free Read in wait_for_completion 1 (2) 2019/02/20 15:22

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x37c2/0x4ec0 kernel/locking/lockdep.c:3290
Read of size 8 at addr ffff8801d28a81a8 by task syz-executor4/12225

CPU: 1 PID: 12225 Comm: syz-executor4 Not tainted 4.19.0-rc8+ #72
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+0x1c4/0x2b4 lib/dump_stack.c:113
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 __lock_acquire+0x37c2/0x4ec0 kernel/locking/lockdep.c:3290
 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3900
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
 _raw_spin_lock_irq+0x61/0x80 kernel/locking/spinlock.c:160
 spin_lock_irq include/linux/spinlock.h:354 [inline]
 do_wait_for_common kernel/sched/completion.c:84 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common kernel/sched/completion.c:115 [inline]
 wait_for_completion+0x436/0x8a0 kernel/sched/completion.c:136
 ucma_destroy_id+0x38a/0x550 drivers/infiniband/core/ucma.c:637
 ucma_write+0x365/0x460 drivers/infiniband/core/ucma.c:1689
 __vfs_write+0x119/0x9f0 fs/read_write.c:485
 vfs_write+0x1fc/0x560 fs/read_write.c:549
 ksys_write+0x101/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fe8a3f8ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569
RDX: 0000000000000018 RSI: 0000000020000280 RDI: 0000000000000005
RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe8a3f8f6d4
R13: 00000000004cb4f8 R14: 00000000004d8b68 R15: 00000000ffffffff

Allocated by task 12210:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620
 kmalloc include/linux/slab.h:513 [inline]
 kzalloc include/linux/slab.h:707 [inline]
 ucma_alloc_ctx+0xce/0x690 drivers/infiniband/core/ucma.c:209
 ucma_create_id+0x27d/0x990 drivers/infiniband/core/ucma.c:500
 ucma_write+0x365/0x460 drivers/infiniband/core/ucma.c:1689
 __vfs_write+0x119/0x9f0 fs/read_write.c:485
 vfs_write+0x1fc/0x560 fs/read_write.c:549
 ksys_write+0x101/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 12210:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xcf/0x230 mm/slab.c:3813
 ucma_free_ctx+0x9e6/0xdb0 drivers/infiniband/core/ucma.c:599
 ucma_close+0x121/0x310 drivers/infiniband/core/ucma.c:1775
 __fput+0x385/0xa30 fs/file_table.c:278
 ____fput+0x15/0x20 fs/file_table.c:309
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
 get_signal+0x155e/0x1980 kernel/signal.c:2343
 do_signal+0x9c/0x21e0 arch/x86/kernel/signal.c:816
 exit_to_usermode_loop+0x2e5/0x380 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801d28a8180
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 40 bytes inside of
 256-byte region [ffff8801d28a8180, ffff8801d28a8280)
The buggy address belongs to the page:
page:ffffea00074a2a00 count:1 mapcount:0 mapping:ffff8801da8007c0 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea000760b108 ffffea0007491148 ffff8801da8007c0
raw: 0000000000000000 ffff8801d28a8040 000000010000000c 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d28a8080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801d28a8100: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801d28a8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff8801d28a8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d28a8280: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/10/20 16:23 upstream 270b77a0f30e ecb386fe .config console log report ci-upstream-kasan-gce-selinux-root
* Struck through repros no longer work on HEAD.