Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in __vma_reservation_common

syzbot
2024-04-13T18:34:36Z

syzbot has found a reproducer for the following issue on:

HEAD commit: 9ed46da14b9b Add linux-next specific files for 20240412
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12bd4457180000
kernel config: https://syzkaller.appspot.com/x/.config?x=7ea0abc478c49859
dashboard link: https://syzkaller.appspot.com/bug?extid=ad1b592fc4483655438b
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1370ea67180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fc649744d68c/disk-9ed46da1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/11eab7b9945d/vmlinux-9ed46da1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e7885afd198d/bzImage-9ed46da1.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/52aaf544deaa/mount_1.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ad1b592fc4483655438b@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in is_vm_hugetlb_page include/linux/hugetlb_inline.h:11 [inline]
BUG: KASAN: slab-use-after-free in vma_resv_map mm/hugetlb.c:1150 [inline]
BUG: KASAN: slab-use-after-free in __vma_reservation_common+0xc9/0x7d0 mm/hugetlb.c:2807
Read of size 8 at addr ffff888077a2f4f8 by task syz-executor.1/5375

CPU: 0 PID: 5375 Comm: syz-executor.1 Not tainted 6.9.0-rc3-next-20240412-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
is_vm_hugetlb_page include/linux/hugetlb_inline.h:11 [inline]
vma_resv_map mm/hugetlb.c:1150 [inline]
__vma_reservation_common+0xc9/0x7d0 mm/hugetlb.c:2807
vma_needs_reservation mm/hugetlb.c:2881 [inline]
restore_reserve_on_error+0x39/0x1d0 mm/hugetlb.c:2931
hugetlb_no_page mm/hugetlb.c:6391 [inline]
hugetlb_fault+0x1ae1/0x3910 mm/hugetlb.c:6487
handle_mm_fault+0x18e8/0x1bb0 mm/memory.c:5701
do_user_addr_fault arch/x86/mm/fault.c:1368 [inline]
handle_page_fault arch/x86/mm/fault.c:1511 [inline]
exc_page_fault+0x459/0x900 arch/x86/mm/fault.c:1569
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f0abea29681
Code: 39 c6 7e 57 4c 8b 5f 20 48 8b 57 28 eb 06 0f 1f 00 4c 89 c2 49 39 d3 74 47 4c 8b 57 18 4c 8d 42 01 89 c1 83 c0 08 4c 89 47 28 <41> 0f b6 14 12 89 47 34 48 d3 e2 49 09 d1 39 f0 7c d5 44 89 ca 29
RSP: 002b:00007f0abf824578 EFLAGS: 00010202
RAX: 0000000000000008 RBX: 00007f0abf824eb8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00007f0abf824670
RBP: 00007f0abf824670 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000020001602 R11: 000000000000609f R12: 0000000000000003
R13: 00007f0abf824f80 R14: 00007f0abf824f40 R15: 00007f0ab5800000
</TASK>

Allocated by task 5373:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:312 [inline]
__kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3897 [inline]
slab_alloc_node mm/slub.c:3957 [inline]
kmem_cache_alloc_noprof+0x135/0x290 mm/slub.c:3964
vm_area_alloc+0x24/0x1d0 kernel/fork.c:467
mmap_region+0xc20/0x2030 mm/mmap.c:2852
do_mmap+0x8ad/0xfa0 mm/mmap.c:1387
vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:573
ksys_mmap_pgoff+0x544/0x720 mm/mmap.c:1433
do_syscall_x64 arch/x86/entry/common.c:74 [inline]
do_syscall_64+0xfa/0x250 arch/x86/entry/common.c:105
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 16:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
__kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2190 [inline]
slab_free mm/slub.c:4393 [inline]
kmem_cache_free+0x145/0x340 mm/slub.c:4468
rcu_do_batch kernel/rcu/tree.c:2565 [inline]
rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2839
__do_softirq+0x2c6/0x980 kernel/softirq.c:554

Last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
__call_rcu_common kernel/rcu/tree.c:3102 [inline]
call_rcu+0x167/0xa70 kernel/rcu/tree.c:3206
remove_vma mm/mmap.c:148 [inline]
remove_mt mm/mmap.c:2334 [inline]
do_vmi_align_munmap+0x155c/0x18c0 mm/mmap.c:2677
do_vmi_munmap+0x24e/0x2d0 mm/mmap.c:2741
mmap_region+0x729/0x2030 mm/mmap.c:2792
do_mmap+0x8ad/0xfa0 mm/mmap.c:1387
vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:573
ksys_mmap_pgoff+0x544/0x720 mm/mmap.c:1433
do_syscall_x64 arch/x86/entry/common.c:74 [inline]
do_syscall_64+0xfa/0x250 arch/x86/entry/common.c:105
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888077a2f4d8
which belongs to the cache vm_area_struct of size 184
The buggy address is located 32 bytes inside of
freed 184-byte region [ffff888077a2f4d8, ffff888077a2f590)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x77a2f
memcg:ffff88801a6ca701
flags: 0xfff80000000000(node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffefff(slab)
raw: 00fff80000000000 ffff8880162a7b40 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000100010 00000001ffffefff ffff88801a6ca701
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 5359, tgid 1476644483 (syz-executor.2), ts 5362, free_ts 103330549507
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1474
prep_new_page mm/page_alloc.c:1482 [inline]
get_page_from_freelist+0x2ce2/0x2d90 mm/page_alloc.c:3444
__alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4702
__alloc_pages_node_noprof include/linux/gfp.h:244 [inline]
alloc_pages_node_noprof include/linux/gfp.h:271 [inline]
alloc_slab_page+0x5f/0x120 mm/slub.c:2259
allocate_slab+0x5a/0x2e0 mm/slub.c:2422
new_slab mm/slub.c:2475 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3624
__slab_alloc+0x58/0xa0 mm/slub.c:3714
__slab_alloc_node mm/slub.c:3767 [inline]
slab_alloc_node mm/slub.c:3945 [inline]
kmem_cache_alloc_noprof+0x1c1/0x290 mm/slub.c:3964
vm_area_alloc+0x24/0x1d0 kernel/fork.c:467
mmap_region+0xc20/0x2030 mm/mmap.c:2852
do_mmap+0x8ad/0xfa0 mm/mmap.c:1387
vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:573
do_syscall_x64 arch/x86/entry/common.c:74 [inline]
do_syscall_64+0xfa/0x250 arch/x86/entry/common.c:105
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5295 tgid 5292 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1094 [inline]
free_unref_folios+0xf23/0x19e0 mm/page_alloc.c:2656
folios_put_refs+0x93a/0xa60 mm/swap.c:1022
free_pages_and_swap_cache+0x5c8/0x690 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
tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:465
exit_mmap+0x44f/0xc80 mm/mmap.c:3325
__mmput+0x115/0x3c0 kernel/fork.c:1346
exit_mm+0x220/0x310 kernel/exit.c:569
do_exit+0x99e/0x27e0 kernel/exit.c:865
do_group_exit+0x207/0x2c0 kernel/exit.c:1027
get_signal+0x16a1/0x1740 kernel/signal.c:2911
arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:111 [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+0xc9/0x370 kernel/entry/common.c:218
do_syscall_64+0x10a/0x250 arch/x86/entry/common.c:111
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff888077a2f380: fb fb fb fb fc fc fc fc fc fc fc fc fa fb fb fb
ffff888077a2f400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888077a2f480: fb fb fb fc fc fc fc fc fc fc fc fa fb fb fb fb
^
ffff888077a2f500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888077a2f580: fb fb fc fc fc fc fc fc fc fc fa fb fb fb fb fb
==================================================================

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