syzbot


KASAN: use-after-free Read in css_free_rwork_fn

Status: auto-closed as invalid on 2022/02/26 22:08
Reported-by: syzbot+9b3893f1729ad3876286@syzkaller.appspotmail.com
First crash: 903d, last: 903d
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 (2) 2 677d 762d 0/2 auto-obsoleted due to no activity on 2022/10/10 20:43
upstream general protection fault in css_free_rwork_fn cgroups 1 1121d 1115d 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+0x548/0x680 kernel/cgroup/cgroup.c:4998
Read of size 4 at addr ffff888116ac8054 by task kworker/0:30/14230

CPU: 0 PID: 14230 Comm: kworker/0:30 Not tainted 5.10.77-syzkaller-01258-g76698ea35fd3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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+0x8d/0x3d0 mm/kasan/report.c:233
 __kasan_report+0x142/0x220 mm/kasan/report.c:419
 kasan_report+0x51/0x70 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+0x548/0x680 kernel/cgroup/cgroup.c:4998
 process_one_work+0x6b4/0xfb0 kernel/workqueue.c:2289
 worker_thread+0xb15/0x1600 kernel/workqueue.c:2435
 kthread+0x371/0x390 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Allocated by task 11550:
 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+0x22a/0x3d0 mm/slub.c:4034
 kmalloc include/linux/slab.h:557 [inline]
 kzalloc+0x1a/0x20 include/linux/slab.h:664
 cgroup_create kernel/cgroup/cgroup.c:5243 [inline]
 cgroup_mkdir+0x322/0x1a40 kernel/cgroup/cgroup.c:5393
 kernfs_iop_mkdir+0x1b0/0x2b0 fs/kernfs/dir.c:1127
 vfs_mkdir+0x435/0x610 fs/namei.c:3725
 ovl_do_mkdir fs/overlayfs/overlayfs.h:159 [inline]
 ovl_mkdir_real fs/overlayfs/dir.c:146 [inline]
 ovl_create_real+0x160/0x380 fs/overlayfs/dir.c:193
 ovl_workdir_create+0x415/0x5e0 fs/overlayfs/super.c:767
 ovl_make_workdir fs/overlayfs/super.c:1311 [inline]
 ovl_get_workdir fs/overlayfs/super.c:1448 [inline]
 ovl_fill_super+0x3887/0x6680 fs/overlayfs/super.c:1988
 mount_nodev+0x57/0xf0 fs/super.c:1465
 ovl_mount+0x2c/0x40 fs/overlayfs/super.c:2072
 legacy_get_tree+0xf0/0x190 fs/fs_context.c:592
 vfs_get_tree+0x89/0x270 fs/super.c:1549
 do_new_mount fs/namespace.c:2899 [inline]
 path_mount+0x1975/0x2ab0 fs/namespace.c:3229
 do_mount fs/namespace.c:3242 [inline]
 __do_sys_mount fs/namespace.c:3450 [inline]
 __se_sys_mount+0x2f7/0x3b0 fs/namespace.c:3427
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3427
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 14230:
 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+0x133/0x170 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:1596 [inline]
 slab_free_freelist_hook+0xcc/0x1a0 mm/slub.c:1622
 slab_free mm/slub.c:3204 [inline]
 kfree+0xd5/0x320 mm/slub.c:4192
 css_free_rwork_fn+0x3f0/0x680 kernel/cgroup/cgroup.c:5020
 process_one_work+0x6b4/0xfb0 kernel/workqueue.c:2289
 worker_thread+0xb15/0x1600 kernel/workqueue.c:2435
 kthread+0x371/0x390 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+0xd3/0xf0 mm/kasan/generic.c:345
 insert_work+0x56/0x330 kernel/workqueue.c:1340
 __queue_work+0x951/0xda0 kernel/workqueue.c:1506
 rcu_work_rcufn+0x47/0x50 kernel/workqueue.c:1749
 rcu_do_batch+0x4cd/0xb40 kernel/rcu/tree.c:2484
 rcu_core+0x822/0x10d0 kernel/rcu/tree.c:2721
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2734
 __do_softirq+0x27e/0x598 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+0xd3/0xf0 mm/kasan/generic.c:345
 __call_rcu kernel/rcu/tree.c:2962 [inline]
 call_rcu+0x134/0x1470 kernel/rcu/tree.c:3036
 queue_rcu_work+0x79/0x90 kernel/workqueue.c:1769
 css_release_work_fn+0x4cf/0x640 kernel/cgroup/cgroup.c:5084
 process_one_work+0x6b4/0xfb0 kernel/workqueue.c:2289
 worker_thread+0xb15/0x1600 kernel/workqueue.c:2435
 kthread+0x371/0x390 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

The buggy address belongs to the object at ffff888116ac8000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 84 bytes inside of
 4096-byte region [ffff888116ac8000, ffff888116ac9000)
The buggy address belongs to the page:
page:ffffea00045ab200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x116ac8
head:ffffea00045ab200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 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 6496, ts 347434975695, free_ts 344795447067
 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+0xa74/0xa90 mm/page_alloc.c:4063
 __alloc_pages_nodemask+0x3c8/0x820 mm/page_alloc.c:5106
 alloc_slab_page mm/slub.c:1807 [inline]
 allocate_slab+0x6b/0x350 mm/slub.c:1809
 new_slab mm/slub.c:1870 [inline]
 new_slab_objects mm/slub.c:2629 [inline]
 ___slab_alloc+0x143/0x2f0 mm/slub.c:2792
 __slab_alloc mm/slub.c:2832 [inline]
 slab_alloc_node mm/slub.c:2914 [inline]
 slab_alloc mm/slub.c:2956 [inline]
 __kmalloc_track_caller+0x299/0x3b0 mm/slub.c:4535
 kmemdup+0x24/0x50 mm/util.c:131
 __devinet_sysctl_register+0xae/0x370 net/ipv4/devinet.c:2560
 devinet_sysctl_register+0x169/0x1e0 net/ipv4/devinet.c:2612
 inetdev_init+0x240/0x590 net/ipv4/devinet.c:276
 inetdev_event+0x205/0x11b0 net/ipv4/devinet.c:1531
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x8e/0xf0 kernel/notifier.c:410
 call_netdevice_notifiers_info net/core/dev.c:2054 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2066 [inline]
 call_netdevice_notifiers net/core/dev.c:2080 [inline]
 register_netdevice+0x1502/0x1ad0 net/core/dev.c:10135
 register_netdev+0x3c/0x50 net/core/dev.c:10235
 ip6_tnl_init_net+0x2d8/0x390 net/ipv6/ip6_tunnel.c:2317
 ops_init+0x199/0x380 net/core/net_namespace.c:152
 setup_net+0x21b/0xa70 net/core/net_namespace.c:342
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+0xbe7/0xc20 mm/page_alloc.c:1611
 free_the_page mm/page_alloc.c:5167 [inline]
 __free_pages+0x2d6/0x4a0 mm/page_alloc.c:5173
 __free_slab+0xdf/0x1a0 mm/slub.c:1895
 free_slab mm/slub.c:1910 [inline]
 discard_slab mm/slub.c:1916 [inline]
 unfreeze_partials+0x17d/0x1b0 mm/slub.c:2410
 put_cpu_partial+0xc8/0x190 mm/slub.c:2446
 __slab_free+0x2eb/0x4e0 mm/slub.c:3096
 do_slab_free mm/slub.c:3192 [inline]
 ___cache_free+0x131/0x150 mm/slub.c:3211
 qlink_free+0x38/0x40 mm/kasan/quarantine.c:146
 qlist_free_all mm/kasan/quarantine.c:165 [inline]
 kasan_quarantine_reduce+0x178/0x1d0 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 mm/slab.h:583 [inline]
 slab_alloc_node mm/slub.c:2948 [inline]
 slab_alloc mm/slub.c:2956 [inline]
 kmem_cache_alloc_trace+0x1a5/0x3a0 mm/slub.c:2973
 kmalloc include/linux/slab.h:552 [inline]
 syslog_print kernel/printk/printk.c:1485 [inline]
 do_syslog+0xfef/0x1430 kernel/printk/printk.c:1642
 __do_sys_syslog kernel/printk/printk.c:1734 [inline]
 __se_sys_syslog kernel/printk/printk.c:1732 [inline]
 __x64_sys_syslog+0x7c/0x90 kernel/printk/printk.c:1732
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Memory state around the buggy address:
 ffff888116ac7f00: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
 ffff888116ac7f80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff888116ac8000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff888116ac8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888116ac8100: 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 1138d9067 P4D 1138d9067 PUD 172342067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 14230 Comm: kworker/0:30 Tainted: G    B             5.10.77-syzkaller-01258-g76698ea35fd3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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+0x42c/0x680 kernel/cgroup/cgroup.c:4998
Code: 18 4d 89 ee 49 c1 ee 03 43 80 3c 26 00 74 08 4c 89 ef e8 47 42 40 00 49 8b 5d 00 48 89 df be 08 00 00 00 e8 46 44 40 00 31 f6 <f0> 48 83 2b 01 0f 94 c3 40 0f 94 c6 31 ff e8 a1 70 06 00 84 db 0f
RSP: 0018:ffffc900040f7cf0 EFLAGS: 00010246

RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81668a8a
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900040f7d28 R08: ffffffff816687ce R09: fffffbfff0dc79b9
R10: fffffbfff0dc79b9 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff888116ac8018 R14: 1ffff11022d59003 R15: ffff888116ac8010
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000153620000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 process_one_work+0x6b4/0xfb0 kernel/workqueue.c:2289
 worker_thread+0xb15/0x1600 kernel/workqueue.c:2435
 kthread+0x371/0x390 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Modules linked in:

CR2: 0000000000000000
---[ end trace bdf3537513addfae ]---
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+0x42c/0x680 kernel/cgroup/cgroup.c:4998
Code: 18 4d 89 ee 49 c1 ee 03 43 80 3c 26 00 74 08 4c 89 ef e8 47 42 40 00 49 8b 5d 00 48 89 df be 08 00 00 00 e8 46 44 40 00 31 f6 <f0> 48 83 2b 01 0f 94 c3 40 0f 94 c6 31 ff e8 a1 70 06 00 84 db 0f
RSP: 0018:ffffc900040f7cf0 EFLAGS: 00010246

RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81668a8a
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900040f7d28 R08: ffffffff816687ce R09: fffffbfff0dc79b9
R10: fffffbfff0dc79b9 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff888116ac8018 R14: 1ffff11022d59003 R15: ffff888116ac8010
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000153620000 CR4: 00000000003526b0
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 47 42 40 00       	callq  0x40425e
  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 46 44 40 00       	callq  0x40446e
  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 a1 70 06 00       	callq  0x670de
  3d:	84 db                	test   %bl,%bl
  3f:	0f                   	.byte 0xf

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/11/28 22:05 android12-5.10-lts 76698ea35fd3 63eeac02 .config console log report info ci2-android-5-10 KASAN: use-after-free Read in css_free_rwork_fn
* Struck through repros no longer work on HEAD.