syzbot


KASAN: use-after-free Read in mas_find

Status: auto-closed as invalid on 2022/08/13 14:04
Reported-by: syzbot+53a201cf0c3cd0082a4e@syzkaller.appspotmail.com
First crash: 110d, last: 102d

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in ma_dead_node lib/maple_tree.c:532 [inline]
BUG: KASAN: use-after-free in mas_next_entry lib/maple_tree.c:4637 [inline]
BUG: KASAN: use-after-free in mas_find+0xada/0xce0 lib/maple_tree.c:5872
Read of size 8 at addr ffff8880324f6800 by task syz-executor.2/18755

CPU: 1 PID: 18755 Comm: syz-executor.2 Not tainted 5.19.0-rc2-next-20220614-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313
 print_report mm/kasan/report.c:429 [inline]
 kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
 ma_dead_node lib/maple_tree.c:532 [inline]
 mas_next_entry lib/maple_tree.c:4637 [inline]
 mas_find+0xada/0xce0 lib/maple_tree.c:5872
 userfaultfd_release+0x239/0x670 fs/userfaultfd.c:875
 __fput+0x277/0x9d0 fs/file_table.c:317
 task_work_run+0xdd/0x1a0 kernel/task_work.c:177
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:169 [inline]
 exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f601b489109
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f601c56f168 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f601b59bf60 RCX: 00007f601b489109
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000003
RBP: 00007f601b4e30ad R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe01b87eff R14: 00007f601c56f300 R15: 0000000000022000
 </TASK>

Allocated by task 18764:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:436 [inline]
 __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:469
 kasan_slab_alloc include/linux/kasan.h:224 [inline]
 slab_post_alloc_hook mm/slab.h:750 [inline]
 kmem_cache_alloc_bulk+0x39f/0x720 mm/slub.c:3728
 mt_alloc_bulk lib/maple_tree.c:151 [inline]
 mas_alloc_nodes+0x2b0/0x6b0 lib/maple_tree.c:1244
 mas_preallocate+0xfb/0x270 lib/maple_tree.c:5584
 __vma_adjust+0x226/0x1900 mm/mmap.c:762
 vma_adjust include/linux/mm.h:2659 [inline]
 __split_vma+0x295/0x530 mm/mmap.c:2302
 do_mas_align_munmap+0x2c0/0xf00 mm/mmap.c:2399
 do_mas_munmap+0x202/0x2c0 mm/mmap.c:2556
 do_munmap+0xc3/0x100 mm/mmap.c:2570
 move_vma+0x776/0xf60 mm/mremap.c:703
 __do_sys_mremap+0x48a/0x16b0 mm/mremap.c:1075
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Freed by task 18755:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track+0x21/0x30 mm/kasan/common.c:45
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328
 kasan_slab_free include/linux/kasan.h:200 [inline]
 slab_free_hook mm/slub.c:1727 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1753
 slab_free mm/slub.c:3507 [inline]
 kmem_cache_free_bulk mm/slub.c:3654 [inline]
 kmem_cache_free_bulk+0x2c0/0xb60 mm/slub.c:3641
 mt_free_bulk lib/maple_tree.c:157 [inline]
 mas_destroy+0x394/0x5c0 lib/maple_tree.c:5688
 mas_store_prealloc+0xec/0x150 lib/maple_tree.c:5569
 __vma_adjust+0x6d7/0x1900 mm/mmap.c:832
 vma_merge+0x6a8/0x870 mm/mmap.c:1132
 userfaultfd_release+0x4c5/0x670 fs/userfaultfd.c:884
 __fput+0x277/0x9d0 fs/file_table.c:317
 task_work_run+0xdd/0x1a0 kernel/task_work.c:177
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:169 [inline]
 exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

The buggy address belongs to the object at ffff8880324f6800
 which belongs to the cache maple_node of size 256
The buggy address is located 0 bytes inside of
 256-byte region [ffff8880324f6800, ffff8880324f6900)

The buggy address belongs to the physical page:
page:ffffea0000c93d80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x324f6
head:ffffea0000c93d80 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff88801184fdc0
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 18764, tgid 18753 (syz-executor.2), ts 788428603514, free_ts 784883019265
 prep_new_page mm/page_alloc.c:2525 [inline]
 get_page_from_freelist+0x1efe/0x3a20 mm/page_alloc.c:4296
 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5512
 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2279
 alloc_slab_page mm/slub.c:1797 [inline]
 allocate_slab+0x26c/0x3c0 mm/slub.c:1942
 new_slab mm/slub.c:2002 [inline]
 ___slab_alloc+0x985/0xd90 mm/slub.c:3002
 kmem_cache_alloc_bulk+0x21c/0x720 mm/slub.c:3704
 mt_alloc_bulk lib/maple_tree.c:151 [inline]
 mas_alloc_nodes+0x2b0/0x6b0 lib/maple_tree.c:1244
 mas_preallocate+0xfb/0x270 lib/maple_tree.c:5584
 __vma_adjust+0x226/0x1900 mm/mmap.c:762
 vma_adjust include/linux/mm.h:2659 [inline]
 __split_vma+0x295/0x530 mm/mmap.c:2302
 do_mas_align_munmap+0x2c0/0xf00 mm/mmap.c:2399
 do_mas_munmap+0x202/0x2c0 mm/mmap.c:2556
 do_munmap+0xc3/0x100 mm/mmap.c:2570
 move_vma+0x776/0xf60 mm/mremap.c:703
 __do_sys_mremap+0x48a/0x16b0 mm/mremap.c:1075
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1443 [inline]
 free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1493
 free_unref_page_prepare mm/page_alloc.c:3373 [inline]
 free_unref_page+0x19/0x560 mm/page_alloc.c:3470
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
 kasan_slab_alloc include/linux/kasan.h:224 [inline]
 slab_post_alloc_hook mm/slab.h:750 [inline]
 slab_alloc_node mm/slub.c:3214 [inline]
 slab_alloc mm/slub.c:3222 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3229 [inline]
 kmem_cache_alloc+0x204/0x3b0 mm/slub.c:3239
 getname_flags.part.0+0x50/0x4f0 fs/namei.c:139
 getname_flags+0x9a/0xe0 include/linux/audit.h:321
 user_path_at_empty+0x2b/0x60 fs/namei.c:2894
 do_readlinkat+0xcd/0x2f0 fs/stat.c:456
 __do_sys_readlink fs/stat.c:489 [inline]
 __se_sys_readlink fs/stat.c:486 [inline]
 __x64_sys_readlink+0x74/0xb0 fs/stat.c:486
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Memory state around the buggy address:
 ffff8880324f6700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880324f6780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880324f6800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880324f6880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880324f6900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (6):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-linux-next-kasan-gce-root 2022/06/14 14:03 linux-next 35d872b9ea5b 0f087040 .config log report info KASAN: use-after-free Read in mas_find
ci-upstream-linux-next-kasan-gce-root 2022/06/14 12:47 linux-next 35d872b9ea5b 0f087040 .config log report info KASAN: use-after-free Read in mas_find
ci-upstream-linux-next-kasan-gce-root 2022/06/14 12:36 linux-next 35d872b9ea5b 0f087040 .config log report info KASAN: use-after-free Read in mas_find
ci-upstream-linux-next-kasan-gce-root 2022/06/14 12:35 linux-next 35d872b9ea5b 0f087040 .config log report info KASAN: use-after-free Read in mas_find
ci-upstream-linux-next-kasan-gce-root 2022/06/10 09:38 linux-next 6d0c80680317 0d5abf15 .config log report info KASAN: use-after-free Read in mas_find
ci-upstream-linux-next-kasan-gce-root 2022/06/05 23:05 linux-next 1cfd968b58a1 c8857892 .config log report info KASAN: use-after-free Read in mas_find
* Struck through repros no longer work on HEAD.