Re: WARNING: held lock freed in uprobe_unregister

From: syzbot
Date: Fri Feb 05 2021 - 15:23:57 EST


syzbot has found a reproducer for the following issue on:

HEAD commit: aa2b8820 Add linux-next specific files for 20210205
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10d455bf500000
kernel config: https://syzkaller.appspot.com/x/.config?x=15c41e44a64aa1a5
dashboard link: https://syzkaller.appspot.com/bug?extid=acc3353d66960200ec63
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13797f80d00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=149b8c18d00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+acc3353d66960200ec63@xxxxxxxxxxxxxxxxxxxxxxxxx

=========================
WARNING: held lock freed!
5.11.0-rc6-next-20210205-syzkaller #0 Not tainted
-------------------------
syz-executor146/8424 is freeing memory ffff888014c83800-ffff888014c839ff, with a lock still held there!
ffff888014c83890 (&uprobe->register_rwsem){+.+.}-{3:3}, at: uprobe_unregister+0x37/0x70 kernel/events/uprobes.c:1115
2 locks held by syz-executor146/8424:
#0: ffffffff8bfe1328 (event_mutex){+.+.}-{3:3}, at: perf_uprobe_destroy+0x23/0x130 kernel/trace/trace_event_perf.c:347
#1: ffff888014c83890 (&uprobe->register_rwsem){+.+.}-{3:3}, at: uprobe_unregister+0x37/0x70 kernel/events/uprobes.c:1115

stack backtrace:
CPU: 0 PID: 8424 Comm: syz-executor146 Not tainted 5.11.0-rc6-next-20210205-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x107/0x163 lib/dump_stack.c:120
print_freed_lock_bug kernel/locking/lockdep.c:6256 [inline]
debug_check_no_locks_freed.cold+0x9d/0xa9 kernel/locking/lockdep.c:6289
slab_free_hook mm/slub.c:1549 [inline]
slab_free_freelist_hook+0xd8/0x1d0 mm/slub.c:1600
slab_free mm/slub.c:3161 [inline]
kfree+0xe5/0x7b0 mm/slub.c:4202
put_uprobe kernel/events/uprobes.c:612 [inline]
put_uprobe+0x13b/0x190 kernel/events/uprobes.c:601
delete_uprobe kernel/events/uprobes.c:947 [inline]
__uprobe_unregister+0x1e5/0x260 kernel/events/uprobes.c:1098
uprobe_unregister+0x42/0x70 kernel/events/uprobes.c:1116
__probe_event_disable+0x11e/0x240 kernel/trace/trace_uprobe.c:1084
probe_event_disable+0x155/0x1c0 kernel/trace/trace_uprobe.c:1171
trace_uprobe_register+0x45a/0x880 kernel/trace/trace_uprobe.c:1459
perf_trace_event_unreg.isra.0+0xac/0x250 kernel/trace/trace_event_perf.c:162
perf_uprobe_destroy+0xbb/0x130 kernel/trace/trace_event_perf.c:349
_free_event+0x2ee/0x1380 kernel/events/core.c:4830
put_event kernel/events/core.c:4924 [inline]
perf_event_release_kernel+0xa24/0xe00 kernel/events/core.c:5039
perf_release+0x33/0x40 kernel/events/core.c:5049
__fput+0x283/0x920 fs/file_table.c:280
task_work_run+0xdd/0x190 kernel/task_work.c:140
exit_task_work include/linux/task_work.h:30 [inline]
do_exit+0xc5c/0x2ae0 kernel/exit.c:825
do_group_exit+0x125/0x310 kernel/exit.c:922
__do_sys_exit_group kernel/exit.c:933 [inline]
__se_sys_exit_group kernel/exit.c:931 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x43db19
Code: Unable to access opcode bytes at RIP 0x43daef.
RSP: 002b:00007ffd9444ab48 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000004ae230 RCX: 000000000043db19
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00000000004ae230
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
==================================================================
BUG: KASAN: use-after-free in __up_write kernel/locking/rwsem.c:1311 [inline]
BUG: KASAN: use-after-free in up_write+0x488/0x560 kernel/locking/rwsem.c:1459
Read of size 8 at addr ffff888014c83888 by task syz-executor146/8424

CPU: 0 PID: 8424 Comm: syz-executor146 Not tainted 5.11.0-rc6-next-20210205-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x107/0x163 lib/dump_stack.c:120
print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232
__kasan_report mm/kasan/report.c:399 [inline]
kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
__up_write kernel/locking/rwsem.c:1311 [inline]
up_write+0x488/0x560 kernel/locking/rwsem.c:1459
uprobe_unregister+0x4a/0x70 kernel/events/uprobes.c:1117
__probe_event_disable+0x11e/0x240 kernel/trace/trace_uprobe.c:1084
probe_event_disable+0x155/0x1c0 kernel/trace/trace_uprobe.c:1171
trace_uprobe_register+0x45a/0x880 kernel/trace/trace_uprobe.c:1459
perf_trace_event_unreg.isra.0+0xac/0x250 kernel/trace/trace_event_perf.c:162
perf_uprobe_destroy+0xbb/0x130 kernel/trace/trace_event_perf.c:349
_free_event+0x2ee/0x1380 kernel/events/core.c:4830
put_event kernel/events/core.c:4924 [inline]
perf_event_release_kernel+0xa24/0xe00 kernel/events/core.c:5039
perf_release+0x33/0x40 kernel/events/core.c:5049
__fput+0x283/0x920 fs/file_table.c:280
task_work_run+0xdd/0x190 kernel/task_work.c:140
exit_task_work include/linux/task_work.h:30 [inline]
do_exit+0xc5c/0x2ae0 kernel/exit.c:825
do_group_exit+0x125/0x310 kernel/exit.c:922
__do_sys_exit_group kernel/exit.c:933 [inline]
__se_sys_exit_group kernel/exit.c:931 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x43db19
Code: Unable to access opcode bytes at RIP 0x43daef.
RSP: 002b:00007ffd9444ab48 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000004ae230 RCX: 000000000043db19
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00000000004ae230
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001

Allocated by task 8424:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:403 [inline]
____kasan_kmalloc mm/kasan/common.c:434 [inline]
____kasan_kmalloc.constprop.0+0xa0/0xd0 mm/kasan/common.c:406
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:686 [inline]
alloc_uprobe kernel/events/uprobes.c:731 [inline]
__uprobe_register+0x19c/0x850 kernel/events/uprobes.c:1167
trace_uprobe_enable kernel/trace/trace_uprobe.c:1063 [inline]
probe_event_enable+0x441/0xa00 kernel/trace/trace_uprobe.c:1129
trace_uprobe_register+0x443/0x880 kernel/trace/trace_uprobe.c:1456
perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
perf_trace_event_init+0x549/0xa20 kernel/trace/trace_event_perf.c:204
perf_uprobe_init+0x16f/0x210 kernel/trace/trace_event_perf.c:336
perf_uprobe_event_init+0xff/0x1c0 kernel/events/core.c:9721
perf_try_init_event+0x12a/0x560 kernel/events/core.c:11038
perf_init_event kernel/events/core.c:11090 [inline]
perf_event_alloc.part.0+0xe3b/0x3960 kernel/events/core.c:11370
perf_event_alloc kernel/events/core.c:11749 [inline]
__do_sys_perf_event_open+0x647/0x2e60 kernel/events/core.c:11847
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 8424:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357
____kasan_slab_free.part.0+0xe1/0x110 mm/kasan/common.c:364
kasan_slab_free include/linux/kasan.h:191 [inline]
slab_free_hook mm/slub.c:1562 [inline]
slab_free_freelist_hook+0x82/0x1d0 mm/slub.c:1600
slab_free mm/slub.c:3161 [inline]
kfree+0xe5/0x7b0 mm/slub.c:4202
put_uprobe kernel/events/uprobes.c:612 [inline]
put_uprobe+0x13b/0x190 kernel/events/uprobes.c:601
delete_uprobe kernel/events/uprobes.c:947 [inline]
__uprobe_unregister+0x1e5/0x260 kernel/events/uprobes.c:1098
uprobe_unregister+0x42/0x70 kernel/events/uprobes.c:1116
__probe_event_disable+0x11e/0x240 kernel/trace/trace_uprobe.c:1084
probe_event_disable+0x155/0x1c0 kernel/trace/trace_uprobe.c:1171
trace_uprobe_register+0x45a/0x880 kernel/trace/trace_uprobe.c:1459
perf_trace_event_unreg.isra.0+0xac/0x250 kernel/trace/trace_event_perf.c:162
perf_uprobe_destroy+0xbb/0x130 kernel/trace/trace_event_perf.c:349
_free_event+0x2ee/0x1380 kernel/events/core.c:4830
put_event kernel/events/core.c:4924 [inline]
perf_event_release_kernel+0xa24/0xe00 kernel/events/core.c:5039
perf_release+0x33/0x40 kernel/events/core.c:5049
__fput+0x283/0x920 fs/file_table.c:280
task_work_run+0xdd/0x190 kernel/task_work.c:140
exit_task_work include/linux/task_work.h:30 [inline]
do_exit+0xc5c/0x2ae0 kernel/exit.c:825
do_group_exit+0x125/0x310 kernel/exit.c:922
__do_sys_exit_group kernel/exit.c:933 [inline]
__se_sys_exit_group kernel/exit.c:931 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff888014c83800
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 136 bytes inside of
512-byte region [ffff888014c83800, ffff888014c83a00)
The buggy address belongs to the page:
page:0000000084dcae2b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14c82
head:0000000084dcae2b order:1 compound_mapcount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 0000000000000000 0000000600000001 ffff888010841c80
raw: 0000000000000000 0000000080080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff888014c83780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888014c83800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888014c83880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888014c83900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888014c83980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================