syzbot


KASAN: stack-out-of-bounds Read in umh_complete

Status: auto-obsoleted due to no activity on 2023/02/05 12:25
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+c92c6a251d49ceceb625@syzkaller.appspotmail.com
First crash: 499d, last: 499d
Discussions (1)
Title Replies (including bot) Last reply
[PATCH v2] umh: fix out of scope usage when the process is being killed 3 (3) 2022/12/15 05:11

Sample crash report:
==================================================================
BUG: KASAN: stack-out-of-bounds in __lock_acquire+0x3ee7/0x56d0 kernel/locking/lockdep.c:4925
Read of size 8 at addr ffffc90015d2fb28 by task kworker/u4:15/5325

CPU: 0 PID: 5325 Comm: kworker/u4:15 Not tainted 6.1.0-rc8-next-20221207-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: events_unbound call_usermodehelper_exec_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:306 [inline]
 print_report+0x15e/0x45d mm/kasan/report.c:417
 kasan_report+0xbf/0x1f0 mm/kasan/report.c:517
 __lock_acquire+0x3ee7/0x56d0 kernel/locking/lockdep.c:4925
 lock_acquire kernel/locking/lockdep.c:5668 [inline]
 lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162
 complete+0x1d/0x1f0 kernel/sched/completion.c:32
 umh_complete+0x32/0x90 kernel/umh.c:59
 call_usermodehelper_exec_sync kernel/umh.c:144 [inline]
 call_usermodehelper_exec_work+0x115/0x180 kernel/umh.c:167
 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
 worker_thread+0x669/0x1090 kernel/workqueue.c:2436
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>

The buggy address belongs to the virtual mapping at
 [ffffc90015d28000, ffffc90015d31000) created by:
 kernel_clone+0xeb/0xa40 kernel/fork.c:2681

The buggy address belongs to the physical page:
page:ffffea00008eaf80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x23abe
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 4645, tgid 4645 (dhcpcd), ts 742840406177, free_ts 741827386172
 prep_new_page mm/page_alloc.c:2531 [inline]
 get_page_from_freelist+0x119c/0x2ce0 mm/page_alloc.c:4283
 __alloc_pages+0x1cb/0x5b0 mm/page_alloc.c:5549
 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2285
 vm_area_alloc_pages mm/vmalloc.c:2989 [inline]
 __vmalloc_area_node mm/vmalloc.c:3057 [inline]
 __vmalloc_node_range+0x978/0x13c0 mm/vmalloc.c:3227
 alloc_thread_stack_node kernel/fork.c:311 [inline]
 dup_task_struct kernel/fork.c:987 [inline]
 copy_process+0x12d2/0x75c0 kernel/fork.c:2097
 kernel_clone+0xeb/0xa40 kernel/fork.c:2681
 __do_sys_clone+0xba/0x100 kernel/fork.c:2822
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1446 [inline]
 free_pcp_prepare+0x65c/0xc00 mm/page_alloc.c:1496
 free_unref_page_prepare mm/page_alloc.c:3369 [inline]
 free_unref_page_list+0x176/0xcd0 mm/page_alloc.c:3510
 release_pages+0xcb1/0x1330 mm/swap.c:1076
 tlb_batch_pages_flush+0xa8/0x1a0 mm/mmu_gather.c:93
 tlb_flush_mmu_free mm/mmu_gather.c:288 [inline]
 tlb_flush_mmu mm/mmu_gather.c:295 [inline]
 tlb_finish_mmu+0x14b/0x7e0 mm/mmu_gather.c:387
 exit_mmap+0x202/0x7b0 mm/mmap.c:3096
 __mmput+0x128/0x4c0 kernel/fork.c:1207
 mmput+0x60/0x70 kernel/fork.c:1229
 exit_mm kernel/exit.c:563 [inline]
 do_exit+0x9ac/0x2950 kernel/exit.c:854
 do_group_exit+0xd4/0x2a0 kernel/exit.c:1010
 get_signal+0x21c3/0x2450 kernel/signal.c:2859
 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
 exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296
 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffffc90015d2fa00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90015d2fa80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90015d2fb00: 00 00 f1 f1 f1 f1 00 00 f2 f2 00 00 00 f3 f3 f3
                                  ^
 ffffc90015d2fb80: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90015d2fc00: 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/12/07 12:25 linux-next 591cd61541b9 d88f3abb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: stack-out-of-bounds Read in umh_complete
* Struck through repros no longer work on HEAD.