syzbot


WARNING: held lock freed in pppol2tp_release

Status: auto-closed as invalid on 2020/02/25 03:46
Reported-by: syzbot+a5d845a409d893a01c59@syzkaller.appspotmail.com
First crash: 1081d, last: 983d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 WARNING: held lock freed in pppol2tp_release (2) syz inconclusive 5 755d 860d 0/1 upstream: reported syz repro on 2020/02/27 22:29

Sample crash report:
protocol 88fb is buggy, dev hsr_slave_0
=========================
WARNING: held lock freed!
4.14.150 #0 Not tainted
-------------------------
syz-executor.4/11232 is freeing memory ffff88809795ce00-ffff88809795d5ff, with a lock still held there!
 (sk_lock-AF_PPPOX){+.+.}, at: [<ffffffff859e3c2e>] lock_sock include/net/sock.h:1462 [inline]
 (sk_lock-AF_PPPOX){+.+.}, at: [<ffffffff859e3c2e>] pppol2tp_release+0x4e/0x300 net/l2tp/l2tp_ppp.c:476
2 locks held by syz-executor.4/11232:
 #0:  (&sb->s_type->i_mutex_key#11){+.+.}, at: [<ffffffff84cd4e89>] inode_lock include/linux/fs.h:718 [inline]
 #0:  (&sb->s_type->i_mutex_key#11){+.+.}, at: [<ffffffff84cd4e89>] __sock_release+0x89/0x2b0 net/socket.c:601
 #1:  (sk_lock-AF_PPPOX){+.+.}, at: [<ffffffff859e3c2e>] lock_sock include/net/sock.h:1462 [inline]
 #1:  (sk_lock-AF_PPPOX){+.+.}, at: [<ffffffff859e3c2e>] pppol2tp_release+0x4e/0x300 net/l2tp/l2tp_ppp.c:476

stack backtrace:
CPU: 1 PID: 11232 Comm: syz-executor.4 Not tainted 4.14.150 #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_freed_lock_bug kernel/locking/lockdep.c:4459 [inline]
 debug_check_no_locks_freed.cold+0x9d/0xa9 kernel/locking/lockdep.c:4492
 kfree+0xb1/0x270 mm/slab.c:3812
 sk_prot_free net/core/sock.c:1504 [inline]
 __sk_destruct+0x450/0x580 net/core/sock.c:1581
 sk_destruct+0xa4/0xd0 net/core/sock.c:1596
 __sk_free+0x54/0x230 net/core/sock.c:1604
 sk_free+0x35/0x40 net/core/sock.c:1615
 sock_put include/net/sock.h:1653 [inline]
 pppol2tp_release+0x27d/0x300 net/l2tp/l2tp_ppp.c:493
 __sock_release+0xce/0x2b0 net/socket.c:602
 sock_close+0x1b/0x30 net/socket.c:1139
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/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+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459f39
RSP: 002b:00007fa77308dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000459f39
RDX: 000000000000002e RSI: 0000000020000180 RDI: 0000000000000006
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa77308e6d4
R13: 00000000004c066b R14: 00000000004d2c18 R15: 00000000ffffffff
kobject: 'loop1' (ffff8880a49131a0): kobject_uevent_env
protocol 88fb is buggy, dev hsr_slave_0
kobject: 'loop1' (ffff8880a49131a0): fill_kobj_path: path = '/devices/virtual/block/loop1'
==================================================================
BUG: KASAN: use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
BUG: KASAN: use-after-free in do_raw_spin_lock+0x1eb/0x230 kernel/locking/spinlock_debug.c:112
Read of size 4 at addr ffff88809795ce8c by task syz-executor.4/11232

CPU: 1 PID: 11232 Comm: syz-executor.4 Not tainted 4.14.150 #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_load4_noabort+0x14/0x20 mm/kasan/report.c:429
 debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
 do_raw_spin_lock+0x1eb/0x230 kernel/locking/spinlock_debug.c:112
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0x3b/0x50 kernel/locking/spinlock.c:176
 spin_lock_bh include/linux/spinlock.h:322 [inline]
 release_sock+0x20/0x1b0 net/core/sock.c:2777
 pppol2tp_release+0x22b/0x300 net/l2tp/l2tp_ppp.c:495
 __sock_release+0xce/0x2b0 net/socket.c:602
 sock_close+0x1b/0x30 net/socket.c:1139
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/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+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459f39
RSP: 002b:00007fa77308dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000459f39
RDX: 000000000000002e RSI: 0000000020000180 RDI: 0000000000000006
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa77308e6d4
R13: 00000000004c066b R14: 00000000004d2c18 R15: 00000000ffffffff

Allocated by task 11241:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15d/0x7a0 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 sk_prot_alloc+0x171/0x2a0 net/core/sock.c:1467
 sk_alloc+0x39/0xd70 net/core/sock.c:1521
 pppol2tp_create+0x32/0x1f0 net/l2tp/l2tp_ppp.c:534
 pppox_create+0xf7/0x210 drivers/net/ppp/pppox.c:134
 __sock_create+0x2f6/0x620 net/socket.c:1275
 sock_create net/socket.c:1315 [inline]
 SYSC_socket net/socket.c:1345 [inline]
 SyS_socket+0xd3/0x170 net/socket.c:1325
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 11232:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 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+0xcc/0x270 mm/slab.c:3815
 sk_prot_free net/core/sock.c:1504 [inline]
 __sk_destruct+0x450/0x580 net/core/sock.c:1581
 sk_destruct+0xa4/0xd0 net/core/sock.c:1596
 __sk_free+0x54/0x230 net/core/sock.c:1604
 sk_free+0x35/0x40 net/core/sock.c:1615
 sock_put include/net/sock.h:1653 [inline]
 pppol2tp_release+0x27d/0x300 net/l2tp/l2tp_ppp.c:493
 __sock_release+0xce/0x2b0 net/socket.c:602
 sock_close+0x1b/0x30 net/socket.c:1139
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/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+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff88809795ce00
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 140 bytes inside of
 2048-byte region [ffff88809795ce00, ffff88809795d600)
The buggy address belongs to the page:
page:ffffea00025e5700 count:1 mapcount:0 mapping:ffff88809795c580 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000008100(slab|head)
raw: 01fffc0000008100 ffff88809795c580 0000000000000000 0000000100000003
raw: ffffea00025ed5a0 ffffea00025bd9a0 ffff8880aa800c40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809795cd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809795ce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88809795ce80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88809795cf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809795cf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2019/10/28 03:46 linux-4.14.y b98aebd29824 25bb509e .config log report
ci2-linux-4-14 2019/08/10 02:00 linux-4.14.y 3ffe1e79c174 acb51638 .config log report
ci2-linux-4-14 2019/07/22 06:57 linux-4.14.y ff33472c282e b3c615f5 .config log report