syzbot


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

Status: upstream: reported on 2024/12/26 18:46
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+1fe1e9bdda75b52f54c6@syzkaller.appspotmail.com
First crash: 4d13h, last: 4d13h
Discussions (1)
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[syzbot] [mm?] KASAN: stack-out-of-bounds Read in save_stack 0 (1) 2024/12/26 18:46

Sample crash report:
loop0: detected capacity change from 0 to 128
VFS: Found a Xenix FS (block size = 1024) on device loop0
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_inode: inode 0,1,2 or nonexistent inode
loop0: detected capacity change from 0 to 4096
ntfs3(loop0): Different NTFS sector size (2048) and media sector size (512).
==================================================================
BUG: KASAN: stack-out-of-bounds in stack_trace_consume_entry+0xbb/0x280 kernel/stacktrace.c:93
Read of size 8 at addr ffffc9000d416b9f by task syz.0.0/5314

CPU: 0 UID: 0 PID: 5314 Comm: syz.0.0 Not tainted 6.13.0-rc3-syzkaller-00289-g48f506ad0b68 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 stack_trace_consume_entry+0xbb/0x280 kernel/stacktrace.c:93
 arch_stack_walk+0x10e/0x150 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 save_stack+0xfb/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x76/0x430 mm/page_owner.c:297
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_folios+0xe39/0x18b0 mm/page_alloc.c:2706
 folios_put_refs+0x76c/0x860 mm/swap.c:962
 free_pages_and_swap_cache+0x2ea/0x690 mm/swap_state.c:332
 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:366 [inline]
 tlb_flush_mmu+0x3a3/0x680 mm/mmu_gather.c:373
 zap_pte_range mm/memory.c:1714 [inline]
 zap_pmd_range mm/memory.c:1753 [inline]
 zap_pud_range mm/memory.c:1782 [inline]
 zap_p4d_range mm/memory.c:1803 [inline]
 unmap_page_range+0x3770/0x4040 mm/memory.c:1824
 unmap_vmas+0x3cc/0x5f0 mm/memory.c:1914
 exit_mmap+0x275/0xc20 mm/mmap.c:1668
 __mmput+0x115/0x3c0 kernel/fork.c:1348
 exit_mm+0x220/0x310 kernel/exit.c:570
 do_exit+0x9ad/0x28e0 kernel/exit.c:925
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 get_signal+0x16b2/0x1750 kernel/signal.c:3017
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f81ce385d29
Code: Unable to access opcode bytes at 0x7f81ce385cff.
RSP: 002b:00007f81cf20d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f81ce575fa8 RCX: 00007f81ce385d29
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f81ce575fac
RBP: 00007f81ce575fa0 R08: 7fffffffffffffff R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 00007f81ce575fac
R13: 0000000000000000 R14: 00007ffc92360370 R15: 00007ffc92360458
 </TASK>

The buggy address belongs to stack of task syz.0.0/5314
 and is located at offset 31 in frame:
 stack_trace_save+0x0/0x1d0 kernel/stacktrace.c:52

This frame has 1 object:
 [32, 56) 'c'

The buggy address belongs to the virtual mapping at
 [ffffc9000d410000, ffffc9000d419000) created by:
 copy_process+0x5d1/0x3d50 kernel/fork.c:2224

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888043d1baf8 pfn:0x43d1b
memcg:ffff88804074fd82
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff888043d1baf8 0000000000000000 00000001ffffffff ffff88804074fd82
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_ZERO), pid 1031, tgid 1031 (kworker/u4:5), ts 67917267952, free_ts 67916351099
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1558
 prep_new_page mm/page_alloc.c:1566 [inline]
 get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3476
 __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4753
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2269
 vm_area_alloc_pages mm/vmalloc.c:3591 [inline]
 __vmalloc_area_node mm/vmalloc.c:3669 [inline]
 __vmalloc_node_range_noprof+0x9c9/0x1380 mm/vmalloc.c:3846
 alloc_thread_stack_node kernel/fork.c:314 [inline]
 dup_task_struct+0x444/0x8c0 kernel/fork.c:1116
 copy_process+0x5d1/0x3d50 kernel/fork.c:2224
 kernel_clone+0x226/0x8e0 kernel/fork.c:2806
 user_mode_thread+0x132/0x1a0 kernel/fork.c:2884
 call_usermodehelper_exec_sync kernel/umh.c:132 [inline]
 call_usermodehelper_exec_work+0x9b/0x230 kernel/umh.c:163
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
page last free pid 5309 tgid 5309 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_folios+0xe39/0x18b0 mm/page_alloc.c:2706
 folios_put_refs+0x76c/0x860 mm/swap.c:962
 free_pages_and_swap_cache+0x5c8/0x690 mm/swap_state.c:335
 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:366 [inline]
 tlb_flush_mmu+0x3a3/0x680 mm/mmu_gather.c:373
 tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:465
 exit_mmap+0x496/0xc20 mm/mmap.c:1681
 __mmput+0x115/0x3c0 kernel/fork.c:1348
 exit_mm+0x220/0x310 kernel/exit.c:570
 do_exit+0x9ad/0x28e0 kernel/exit.c:925
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 __do_sys_exit_group kernel/exit.c:1098 [inline]
 __se_sys_exit_group kernel/exit.c:1096 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1096
 x64_sys_call+0x26a8/0x26b0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffffc9000d416a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000d416b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc9000d416b80: f1 f1 f1 f1 00 00 00 f3 f3 f3 f3 f3 00 00 00 00
                            ^
 ffffc9000d416c00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
 ffffc9000d416c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/22 11:13 upstream 48f506ad0b68 b4fbdbd4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: stack-out-of-bounds Read in save_stack
* Struck through repros no longer work on HEAD.