Re: [syzbot] [mm?] WARNING in __folio_rmap_sanity_checks (2)

syzbot
2024-12-30T12:20:03Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in filemap_map_pages

XFS (loop4): Quotacheck: Done.
==================================================================
BUG: KASAN: slab-use-after-free in ptep_get include/linux/pgtable.h:338 [inline]
BUG: KASAN: slab-use-after-free in filemap_map_folio_range mm/filemap.c:3632 [inline]
BUG: KASAN: slab-use-after-free in filemap_map_pages+0xdbe/0x1ab0 mm/filemap.c:3753
Read of size 8 at addr ffff8880612ed000 by task syz.4.28/7015

CPU: 1 UID: 0 PID: 7015 Comm: syz.4.28 Not tainted 6.13.0-rc3-next-20241220-syzkaller-05236-g8155b4ef3466-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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
ptep_get include/linux/pgtable.h:338 [inline]
filemap_map_folio_range mm/filemap.c:3632 [inline]
filemap_map_pages+0xdbe/0x1ab0 mm/filemap.c:3753
do_fault_around mm/memory.c:5351 [inline]
do_read_fault mm/memory.c:5384 [inline]
do_fault mm/memory.c:5527 [inline]
do_pte_missing mm/memory.c:4048 [inline]
handle_pte_fault+0x3888/0x5ee0 mm/memory.c:5890
__handle_mm_fault mm/memory.c:6033 [inline]
handle_mm_fault+0x11f5/0x1d50 mm/memory.c:6202
faultin_page mm/gup.c:1196 [inline]
__get_user_pages+0x1a92/0x4140 mm/gup.c:1491
populate_vma_page_range+0x264/0x330 mm/gup.c:1929
__mm_populate+0x27a/0x460 mm/gup.c:2032
mm_populate include/linux/mm.h:3400 [inline]
vm_mmap_pgoff+0x303/0x430 mm/util.c:585
ksys_mmap_pgoff+0x4eb/0x720 mm/mmap.c:607
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
RIP: 0033:0x7f3a46985d29
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3a47799038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f3a46b75fa0 RCX: 00007f3a46985d29
RDX: 0000000000000002 RSI: 0000000000b36000 RDI: 0000000020000000
RBP: 00007f3a46a01b08 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000000028011 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3a46b75fa0 R15: 00007ffd9346e698
</TASK>

Allocated by task 6993:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4294 [inline]
__kmalloc_noprof+0x285/0x4c0 mm/slub.c:4306
kmalloc_noprof include/linux/slab.h:905 [inline]
kzalloc_noprof include/linux/slab.h:1037 [inline]
tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
tomoyo_encode+0x26f/0x540 security/tomoyo/realpath.c:80
tomoyo_realpath_from_path+0x59e/0x5e0 security/tomoyo/realpath.c:283
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x2b7/0x740 security/tomoyo/file.c:822
security_inode_getattr+0x130/0x330 security/security.c:2377
vfs_getattr+0x2a/0x3a0 fs/stat.c:243
vfs_fstat fs/stat.c:265 [inline]
vfs_fstatat+0xa8/0x130 fs/stat.c:364
__do_sys_newfstatat fs/stat.c:530 [inline]
__se_sys_newfstatat fs/stat.c:524 [inline]
__x64_sys_newfstatat+0x11d/0x1a0 fs/stat.c:524
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

Freed by task 6993:
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:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2353 [inline]
slab_free mm/slub.c:4609 [inline]
kfree+0x196/0x430 mm/slub.c:4757
tomoyo_path_perm+0x59c/0x740 security/tomoyo/file.c:842
security_inode_getattr+0x130/0x330 security/security.c:2377
vfs_getattr+0x2a/0x3a0 fs/stat.c:243
vfs_fstat fs/stat.c:265 [inline]
vfs_fstatat+0xa8/0x130 fs/stat.c:364
__do_sys_newfstatat fs/stat.c:530 [inline]
__se_sys_newfstatat fs/stat.c:524 [inline]
__x64_sys_newfstatat+0x11d/0x1a0 fs/stat.c:524
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

The buggy address belongs to the object at ffff8880612ed000
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes inside of
freed 64-byte region [ffff8880612ed000, ffff8880612ed040)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x612ed
anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801ac418c0 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000200020 00000000f5000000 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 6630, tgid 6630 (syz-executor), ts 112518327578, free_ts 108816210359
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
prep_new_page mm/page_alloc.c:1559 [inline]
get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477
__alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4754
alloc_pages_mpol+0x30e/0x550 mm/mempolicy.c:2270
alloc_slab_page mm/slub.c:2423 [inline]
allocate_slab+0x8f/0x3a0 mm/slub.c:2587
new_slab mm/slub.c:2640 [inline]
___slab_alloc+0xc27/0x14a0 mm/slub.c:3826
__slab_alloc+0x58/0xa0 mm/slub.c:3916
__slab_alloc_node mm/slub.c:3991 [inline]
slab_alloc_node mm/slub.c:4152 [inline]
__do_kmalloc_node mm/slub.c:4293 [inline]
__kmalloc_noprof+0x2e6/0x4c0 mm/slub.c:4306
kmalloc_noprof include/linux/slab.h:905 [inline]
kzalloc_noprof include/linux/slab.h:1037 [inline]
kobject_get_path+0xb8/0x230 lib/kobject.c:161
kobject_uevent_env+0x2a5/0x8e0 lib/kobject_uevent.c:545
netdev_queue_add_kobject net/core/net-sysfs.c:1800 [inline]
netdev_queue_update_kobjects+0x28d/0x550 net/core/net-sysfs.c:1841
register_queue_kobjects net/core/net-sysfs.c:1903 [inline]
netdev_register_kobject+0x234/0x2e0 net/core/net-sysfs.c:2143
register_netdevice+0x12c5/0x1b00 net/core/dev.c:10599
veth_newlink+0x3fd/0xb00 drivers/net/veth.c:1815
rtnl_newlink_create+0x2ee/0xa40 net/core/rtnetlink.c:3786
__rtnl_newlink net/core/rtnetlink.c:3897 [inline]
rtnl_newlink+0x1c7e/0x2210 net/core/rtnetlink.c:4012
page last free pid 5208 tgid 5208 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1127 [inline]
free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660
__slab_free+0x2c2/0x380 mm/slub.c:4520
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4115 [inline]
slab_alloc_node mm/slub.c:4164 [inline]
kmem_cache_alloc_lru_noprof+0x1dd/0x390 mm/slub.c:4183
__d_alloc+0x31/0x700 fs/dcache.c:1646
d_alloc fs/dcache.c:1726 [inline]
d_alloc_parallel+0xdf/0x1600 fs/dcache.c:2490
lookup_open fs/namei.c:3571 [inline]
open_last_lookups fs/namei.c:3748 [inline]
path_openat+0x9e6/0x3580 fs/namei.c:3984
do_filp_open+0x27f/0x4e0 fs/namei.c:4014
do_sys_openat2+0x13e/0x1d0 fs/open.c:1427
do_sys_open fs/open.c:1442 [inline]
__do_sys_openat fs/open.c:1458 [inline]
__se_sys_openat fs/open.c:1453 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1453
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:
ffff8880612ecf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8880612ecf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880612ed000: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
^
ffff8880612ed080: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff8880612ed100: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
==================================================================

Tested on:

commit: 8155b4ef Add linux-next specific files for 20241220
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15f4a6df980000
kernel config: https://syzkaller.appspot.com/x/.config?x=9c90bb7161a56c88
dashboard link: https://syzkaller.appspot.com/bug?extid=c0673e1f1f054fac28c2
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=17f4550f980000