syzbot


KASAN: slab-use-after-free Read in process_srcu

Status: moderation: reported on 2024/05/20 02:53
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+f44cfed96a2c671bc329@syzkaller.appspotmail.com
First crash: 30d, last: 14d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: uninit-value in process_srcu block 3 431d 474d 0/27 auto-obsoleted due to no activity on 2023/07/10 12:54

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: slab-use-after-free in atomic_long_read include/linux/atomic/atomic-instrumented.h:3188 [inline]
BUG: KASAN: slab-use-after-free in __mutex_unlock_slowpath+0xb0/0x650 kernel/locking/mutex.c:921
Read of size 8 at addr ffff88805acb8820 by task kworker/0:5/5295

CPU: 0 PID: 5295 Comm: kworker/0:5 Not tainted 6.10.0-rc1-syzkaller-00267-gcc8ed4d0a848 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: rcu_gp process_srcu
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 atomic_long_read include/linux/atomic/atomic-instrumented.h:3188 [inline]
 __mutex_unlock_slowpath+0xb0/0x650 kernel/locking/mutex.c:921
 srcu_gp_end kernel/rcu/srcutree.c:919 [inline]
 srcu_advance_state kernel/rcu/srcutree.c:1707 [inline]
 process_srcu+0xe46/0x1730 kernel/rcu/srcutree.c:1811
 process_one_work+0x958/0x1ad0 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 5444:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387
 kmalloc_noprof include/linux/slab.h:660 [inline]
 kzalloc_noprof include/linux/slab.h:778 [inline]
 init_srcu_struct_fields+0x8ec/0xd90 kernel/rcu/srcutree.c:240
 bch2_fs_btree_iter_init+0xfd/0x160 fs/bcachefs/btree_iter.c:3443
 bch2_fs_alloc+0x190b/0x2550 fs/bcachefs/super.c:913
 bch2_fs_open+0x713/0x10f0 fs/bcachefs/super.c:2102
 bch2_mount+0xdc9/0x1140 fs/bcachefs/fs.c:1917
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1780
 do_new_mount fs/namespace.c:3352 [inline]
 path_mount+0x6e1/0x1f10 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount fs/namespace.c:3875 [inline]
 __ia32_sys_mount+0x295/0x320 fs/namespace.c:3875
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Freed by task 5235:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2195 [inline]
 slab_free mm/slub.c:4436 [inline]
 kfree+0x12a/0x3b0 mm/slub.c:4557
 cleanup_srcu_struct+0x322/0x520 kernel/rcu/srcutree.c:678
 bch2_fs_btree_iter_exit+0x46e/0x630 fs/bcachefs/btree_iter.c:3410
 __bch2_fs_free fs/bcachefs/super.c:556 [inline]
 bch2_fs_release+0x117/0x820 fs/bcachefs/super.c:603
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1fa/0x5b0 lib/kobject.c:737
 deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
 deactivate_super+0xde/0x100 fs/super.c:506
 cleanup_mnt+0x222/0x450 fs/namespace.c:1267
 task_work_run+0x14e/0x250 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218
 __do_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Last potentially related work creation:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xba/0xd0 mm/kasan/generic.c:541
 insert_work+0x36/0x230 kernel/workqueue.c:2207
 __queue_work+0x944/0x1020 kernel/workqueue.c:2359
 __queue_delayed_work+0x21b/0x2e0 kernel/workqueue.c:2527
 queue_delayed_work_on+0x12a/0x150 kernel/workqueue.c:2572
 srcu_gp_end kernel/rcu/srcutree.c:928 [inline]
 srcu_advance_state kernel/rcu/srcutree.c:1707 [inline]
 process_srcu+0x119a/0x1730 kernel/rcu/srcutree.c:1811
 process_one_work+0x958/0x1ad0 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Second to last potentially related work creation:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xba/0xd0 mm/kasan/generic.c:541
 insert_work+0x36/0x230 kernel/workqueue.c:2207
 __queue_work+0x944/0x1020 kernel/workqueue.c:2359
 flush_delayed_work+0xe0/0x100 kernel/workqueue.c:4252
 cleanup_srcu_struct+0x72/0x520 kernel/rcu/srcutree.c:655
 bch2_fs_btree_iter_exit+0x46e/0x630 fs/bcachefs/btree_iter.c:3410
 __bch2_fs_free fs/bcachefs/super.c:556 [inline]
 bch2_fs_release+0x117/0x820 fs/bcachefs/super.c:603
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1fa/0x5b0 lib/kobject.c:737
 deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
 deactivate_super+0xde/0x100 fs/super.c:506
 cleanup_mnt+0x222/0x450 fs/namespace.c:1267
 task_work_run+0x14e/0x250 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218
 __do_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

The buggy address belongs to the object at ffff88805acb8800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 32 bytes inside of
 freed 1024-byte region [ffff88805acb8800, ffff88805acb8c00)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5acb8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 04fff00000000040 ffff888015442dc0 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000100010 00000001ffffefff 0000000000000000
head: 04fff00000000040 ffff888015442dc0 0000000000000000 dead000000000001
head: 0000000000000000 0000000000100010 00000001ffffefff 0000000000000000
head: 04fff00000000003 ffffea00016b2e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 35, tgid 35 (kworker/3:0), ts 50728266623, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1468
 prep_new_page mm/page_alloc.c:1476 [inline]
 get_page_from_freelist+0x136a/0x2df0 mm/page_alloc.c:3402
 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4660
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page+0x56/0x110 mm/slub.c:2264
 allocate_slab mm/slub.c:2427 [inline]
 new_slab+0x84/0x260 mm/slub.c:2480
 ___slab_alloc+0xdac/0x1870 mm/slub.c:3666
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3756
 __slab_alloc_node mm/slub.c:3809 [inline]
 slab_alloc_node mm/slub.c:3988 [inline]
 __do_kmalloc_node mm/slub.c:4120 [inline]
 kmalloc_node_track_caller_noprof+0x365/0x440 mm/slub.c:4141
 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:597
 __alloc_skb+0x164/0x380 net/core/skbuff.c:666
 alloc_skb include/linux/skbuff.h:1308 [inline]
 nlmsg_new include/net/netlink.h:1015 [inline]
 br_info_notify+0x10f/0x2e0 net/bridge/br_netlink.c:647
 br_port_carrier_check+0x264/0x4c0 net/bridge/br_if.c:89
 br_device_event+0x50b/0x920 net/bridge/br.c:89
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1992
 netdev_state_change net/core/dev.c:1374 [inline]
 netdev_state_change+0x115/0x150 net/core/dev.c:1367
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88805acb8700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805acb8780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88805acb8800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88805acb8880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805acb8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/01 14:50 upstream cc8ed4d0a848 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-use-after-free Read in process_srcu
2024/05/16 02:51 upstream 33e02dc69afb ef5d53ed .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-use-after-free Read in process_srcu
2024/05/31 23:00 upstream d8ec19857b09 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 UBSAN: array-index-out-of-bounds in process_srcu
* Struck through repros no longer work on HEAD.