syzbot


KASAN: use-after-free Read in css_free_rwork_fn (2)

Status: auto-obsoleted due to no activity on 2022/10/10 20:43
Reported-by: syzbot+f9bca07d5983c6aeff0f@syzkaller.appspotmail.com
First crash: 684d, last: 600d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 KASAN: use-after-free Read in css_free_rwork_fn 1 826d 826d 0/2 auto-closed as invalid on 2022/02/26 22:08
upstream general protection fault in css_free_rwork_fn cgroups 1 1044d 1038d 0/26 auto-closed as invalid on 2021/06/23 23:57

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in css_put include/linux/cgroup.h:406 [inline]
BUG: KASAN: use-after-free in cgroup_put include/linux/cgroup.h:435 [inline]
BUG: KASAN: use-after-free in css_free_rwork_fn+0x545/0x680 kernel/cgroup/cgroup.c:5066
Read of size 4 at addr ffff888143248054 by task kworker/0:212/27277

CPU: 0 PID: 27277 Comm: kworker/0:212 Not tainted 5.10.118-syzkaller-00163-gfa7f6a5f56d9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Workqueue: cgroup_destroy css_free_rwork_fn
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3c0 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report+0x1a4/0x1f0 mm/kasan/report.c:436
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 css_put include/linux/cgroup.h:406 [inline]
 cgroup_put include/linux/cgroup.h:435 [inline]
 css_free_rwork_fn+0x545/0x680 kernel/cgroup/cgroup.c:5066
 process_one_work+0x726/0xc10 kernel/workqueue.c:2296
 worker_thread+0xb27/0x1550 kernel/workqueue.c:2442
 kthread+0x349/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Allocated by task 15908:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:428 [inline]
 ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:507
 __kasan_kmalloc+0x9/0x10 mm/kasan/common.c:516
 kasan_kmalloc include/linux/kasan.h:269 [inline]
 __kmalloc+0x1f7/0x360 mm/slub.c:4042
 kmalloc include/linux/slab.h:557 [inline]
 kzalloc include/linux/slab.h:664 [inline]
 cgroup_create kernel/cgroup/cgroup.c:5311 [inline]
 cgroup_mkdir+0x2d7/0x15c0 kernel/cgroup/cgroup.c:5461
 kernfs_iop_mkdir+0x1ad/0x2b0 fs/kernfs/dir.c:1127
 vfs_mkdir+0x435/0x610 fs/namei.c:3725
 do_mkdirat+0x1b6/0x2d0 fs/namei.c:3748
 __do_sys_mkdirat fs/namei.c:3759 [inline]
 __se_sys_mkdirat fs/namei.c:3757 [inline]
 __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3757
 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 27277:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:46
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:357
 ____kasan_slab_free+0x121/0x160 mm/kasan/common.c:360
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:368
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:1604 [inline]
 slab_free_freelist_hook+0xcc/0x1a0 mm/slub.c:1630
 slab_free mm/slub.c:3212 [inline]
 kfree+0xc3/0x290 mm/slub.c:4200
 css_free_rwork_fn+0x3ed/0x680 kernel/cgroup/cgroup.c:5088
 process_one_work+0x726/0xc10 kernel/workqueue.c:2296
 worker_thread+0xb27/0x1550 kernel/workqueue.c:2442
 kthread+0x349/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Last potentially related work creation:
 kasan_save_stack+0x36/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xca/0xf0 mm/kasan/generic.c:345
 insert_work+0x56/0x330 kernel/workqueue.c:1348
 __queue_work+0x971/0xd30 kernel/workqueue.c:1514
 rcu_work_rcufn+0x47/0x50 kernel/workqueue.c:1757
 rcu_do_batch+0x59e/0xc40 kernel/rcu/tree.c:2485
 rcu_core+0x59b/0xe30 kernel/rcu/tree.c:2726
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2739
 __do_softirq+0x27e/0x596 kernel/softirq.c:305

Second to last potentially related work creation:
 kasan_save_stack+0x36/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xca/0xf0 mm/kasan/generic.c:345
 __call_rcu kernel/rcu/tree.c:2967 [inline]
 call_rcu+0x140/0x1300 kernel/rcu/tree.c:3041
 queue_rcu_work+0x7f/0xa0 kernel/workqueue.c:1777
 css_release_work_fn+0x4cf/0x640 kernel/cgroup/cgroup.c:5152
 process_one_work+0x726/0xc10 kernel/workqueue.c:2296
 worker_thread+0xb27/0x1550 kernel/workqueue.c:2442
 kthread+0x349/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

The buggy address belongs to the object at ffff888143248000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 84 bytes inside of
 4096-byte region [ffff888143248000, ffff888143249000)
The buggy address belongs to the page:
page:ffffea00050c9200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x143248
head:ffffea00050c9200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 ffffea0004af3800 0000000200000002 ffff888100042c00
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 28969, ts 1792738996212, free_ts 1791423619430
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2385 [inline]
 prep_new_page mm/page_alloc.c:2391 [inline]
 get_page_from_freelist+0x745/0x760 mm/page_alloc.c:4067
 __alloc_pages_nodemask+0x3b6/0x890 mm/page_alloc.c:5117
 alloc_slab_page mm/slub.c:1815 [inline]
 allocate_slab+0x78/0x540 mm/slub.c:1817
 new_slab mm/slub.c:1878 [inline]
 new_slab_objects mm/slub.c:2637 [inline]
 ___slab_alloc+0x131/0x2e0 mm/slub.c:2800
 __slab_alloc+0x63/0xa0 mm/slub.c:2840
 slab_alloc_node mm/slub.c:2922 [inline]
 slab_alloc mm/slub.c:2964 [inline]
 __kmalloc_track_caller+0x23e/0x350 mm/slub.c:4545
 __kmalloc_reserve net/core/skbuff.c:143 [inline]
 __alloc_skb+0xbe/0x580 net/core/skbuff.c:211
 alloc_skb include/linux/skbuff.h:1101 [inline]
 nlmsg_new include/net/netlink.h:953 [inline]
 rtmsg_ifinfo_build_skb+0x7f/0x180 net/core/rtnetlink.c:3819
 rtmsg_ifinfo_event net/core/rtnetlink.c:3855 [inline]
 rtmsg_ifinfo+0x77/0x120 net/core/rtnetlink.c:3864
 register_netdevice+0x150f/0x1790 net/core/dev.c:10166
 register_netdev+0x3c/0x50 net/core/dev.c:10245
 sit_init_net+0x243/0x480 net/ipv6/sit.c:1914
 ops_init+0x19e/0x390 net/core/net_namespace.c:152
 setup_net+0x21b/0xa70 net/core/net_namespace.c:344
 copy_net_ns+0x317/0x520 net/core/net_namespace.c:485
 create_new_namespaces+0x425/0x710 kernel/nsproxy.c:110
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1331 [inline]
 __free_pages_ok+0x7f8/0x830 mm/page_alloc.c:1611
 free_the_page mm/page_alloc.c:5178 [inline]
 __free_pages+0x383/0x570 mm/page_alloc.c:5185
 __free_slab+0xd3/0x190 mm/slub.c:1903
 free_slab mm/slub.c:1918 [inline]
 discard_slab+0x29/0x40 mm/slub.c:1924
 __slab_free+0x31d/0x3a0 mm/slub.c:3140
 do_slab_free mm/slub.c:3200 [inline]
 ___cache_free+0x11f/0x140 mm/slub.c:3219
 qlink_free+0x38/0x40 mm/kasan/quarantine.c:146
 qlist_free_all+0x4c/0xc0 mm/kasan/quarantine.c:165
 kasan_quarantine_reduce+0x15a/0x170 mm/kasan/quarantine.c:272
 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:438
 kasan_slab_alloc include/linux/kasan.h:259 [inline]
 slab_post_alloc_hook include/../mm/slab.h:583 [inline]
 slab_alloc_node mm/slub.c:2956 [inline]
 slab_alloc mm/slub.c:2964 [inline]
 kmem_cache_alloc+0x16c/0x300 mm/slub.c:2969
 kmem_cache_alloc_node include/linux/slab.h:423 [inline]
 __alloc_skb+0x7e/0x580 net/core/skbuff.c:199
 alloc_skb_fclone include/linux/skbuff.h:1151 [inline]
 sk_stream_alloc_skb+0x1e5/0xa80 net/ipv4/tcp.c:890
 tcp_sendmsg_locked+0xd81/0x3be0 net/ipv4/tcp.c:1298
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1450
 inet_sendmsg+0xa1/0xc0 net/ipv4/af_inet.c:821

Memory state around the buggy address:
 ffff888143247f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888143247f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888143248000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff888143248080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888143248100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 27277 Comm: kworker/0:212 Tainted: G    B             5.10.118-syzkaller-00163-gfa7f6a5f56d9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Workqueue: cgroup_destroy css_free_rwork_fn
RIP: 0010:arch_atomic64_sub_and_test arch/x86/include/asm/atomic64_64.h:76 [inline]
RIP: 0010:atomic64_sub_and_test include/asm-generic/atomic-instrumented.h:1549 [inline]
RIP: 0010:atomic_long_sub_and_test include/asm-generic/atomic-long.h:461 [inline]
RIP: 0010:percpu_ref_put_many include/linux/percpu-refcount.h:321 [inline]
RIP: 0010:percpu_ref_put include/linux/percpu-refcount.h:338 [inline]
RIP: 0010:css_put include/linux/cgroup.h:407 [inline]
RIP: 0010:cgroup_put include/linux/cgroup.h:435 [inline]
RIP: 0010:css_free_rwork_fn+0x429/0x680 kernel/cgroup/cgroup.c:5066
Code: 18 4d 89 ee 49 c1 ee 03 43 80 3c 26 00 74 08 4c 89 ef e8 aa bb 40 00 49 8b 5d 00 48 89 df be 08 00 00 00 e8 a9 bd 40 00 31 f6 <f0> 48 83 2b 01 0f 94 c3 40 0f 94 c6 31 ff e8 44 c3 06 00 84 db 0f
RSP: 0018:ffffc90006c3fce0 EFLAGS: 00010246
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8165f2a7
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90006c3fd18 R08: ffffffff8165efee R09: fffffbfff0d860f9
R10: fffffbfff0d860f9 R11: 1ffffffff0d860f8 R12: dffffc0000000000
R13: ffff888143248018 R14: 1ffff11028649003 R15: ffff888143248010
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000010ee9e000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 process_one_work+0x726/0xc10 kernel/workqueue.c:2296
 worker_thread+0xb27/0x1550 kernel/workqueue.c:2442
 kthread+0x349/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Modules linked in:
CR2: 0000000000000000
---[ end trace 2d6df5ff1d9336c8 ]---
RIP: 0010:arch_atomic64_sub_and_test arch/x86/include/asm/atomic64_64.h:76 [inline]
RIP: 0010:atomic64_sub_and_test include/asm-generic/atomic-instrumented.h:1549 [inline]
RIP: 0010:atomic_long_sub_and_test include/asm-generic/atomic-long.h:461 [inline]
RIP: 0010:percpu_ref_put_many include/linux/percpu-refcount.h:321 [inline]
RIP: 0010:percpu_ref_put include/linux/percpu-refcount.h:338 [inline]
RIP: 0010:css_put include/linux/cgroup.h:407 [inline]
RIP: 0010:cgroup_put include/linux/cgroup.h:435 [inline]
RIP: 0010:css_free_rwork_fn+0x429/0x680 kernel/cgroup/cgroup.c:5066
Code: 18 4d 89 ee 49 c1 ee 03 43 80 3c 26 00 74 08 4c 89 ef e8 aa bb 40 00 49 8b 5d 00 48 89 df be 08 00 00 00 e8 a9 bd 40 00 31 f6 <f0> 48 83 2b 01 0f 94 c3 40 0f 94 c6 31 ff e8 44 c3 06 00 84 db 0f
RSP: 0018:ffffc90006c3fce0 EFLAGS: 00010246
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8165f2a7
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90006c3fd18 R08: ffffffff8165efee R09: fffffbfff0d860f9
R10: fffffbfff0d860f9 R11: 1ffffffff0d860f8 R12: dffffc0000000000
R13: ffff888143248018 R14: 1ffff11028649003 R15: ffff888143248010
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000010ee9e000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	18 4d 89             	sbb    %cl,-0x77(%rbp)
   3:	ee                   	out    %al,(%dx)
   4:	49 c1 ee 03          	shr    $0x3,%r14
   8:	43 80 3c 26 00       	cmpb   $0x0,(%r14,%r12,1)
   d:	74 08                	je     0x17
   f:	4c 89 ef             	mov    %r13,%rdi
  12:	e8 aa bb 40 00       	callq  0x40bbc1
  17:	49 8b 5d 00          	mov    0x0(%r13),%rbx
  1b:	48 89 df             	mov    %rbx,%rdi
  1e:	be 08 00 00 00       	mov    $0x8,%esi
  23:	e8 a9 bd 40 00       	callq  0x40bdd1
  28:	31 f6                	xor    %esi,%esi
* 2a:	f0 48 83 2b 01       	lock subq $0x1,(%rbx) <-- trapping instruction
  2f:	0f 94 c3             	sete   %bl
  32:	40 0f 94 c6          	sete   %sil
  36:	31 ff                	xor    %edi,%edi
  38:	e8 44 c3 06 00       	callq  0x6c381
  3d:	84 db                	test   %bl,%bl
  3f:	0f                   	.byte 0xf

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/07/12 20:43 android12-5.10-lts fa7f6a5f56d9 d91dd8ea .config console log report info ci2-android-5-10-perf KASAN: use-after-free Read in css_free_rwork_fn
2022/04/19 03:10 android12-5.10-lts 414e6c8e941c 8bcc32a6 .config console log report info ci2-android-5-10-perf KASAN: use-after-free Read in css_free_rwork_fn
* Struck through repros no longer work on HEAD.