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

[syzbot <syzbot+c0673e1f1f054fac28c2@syzkaller.appspotmail.com>]

Hello,

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

==================================================================
BUG: KASAN: use-after-free in ptep_get include/linux/pgtable.h:338 [inline]
BUG: KASAN: use-after-free in filemap_map_folio_range mm/filemap.c:3632 [inline]
BUG: KASAN: use-after-free in filemap_map_pages+0xefb/0x1aa0 mm/filemap.c:3753
Read of size 8 at addr ffff88807b524000 by task syz.0.16/6781

CPU: 1 UID: 0 PID: 6781 Comm: syz.0.16 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+0xefb/0x1aa0 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: 0033:0x7fe41b185d29
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:00007fe41bff6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fe41b375fa0 RCX: 00007fe41b185d29
RDX: 0000000000000002 RSI: 0000000000b36000 RDI: 0000000020000000
RBP: 00007fe41b201b08 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000000028011 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe41b375fa0 R15: 00007ffedf5c4578
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7b524
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 00fff00000000000 ffff88813fffbed0 ffffea000088e108 0000000000000000
raw: 0000000000000000 0000000000000002 00000000f0000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6034, tgid 6034 (dhcpcd-run-hook), ts 82273930287, free_ts 120498877039
 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]
 tomoyo_realpath_from_path+0xcf/0x5e0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x258/0x4f0 security/tomoyo/file.c:771
 security_file_open+0xac/0x250 security/security.c:3114
 do_dentry_open+0x320/0x1960 fs/open.c:932
 vfs_open+0x3b/0x370 fs/open.c:1085
 do_open fs/namei.c:3828 [inline]
 path_openat+0x2c74/0x3580 fs/namei.c:3987
 do_filp_open+0x27f/0x4e0 fs/namei.c:4014
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1427
page last free pid 6781 tgid 6780 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
 discard_slab mm/slub.c:2684 [inline]
 __put_partials+0x160/0x1c0 mm/slub.c:3153
 put_cpu_partial+0x17c/0x250 mm/slub.c:3228
 __slab_free+0x290/0x380 mm/slub.c:4479
 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_noprof+0x1d9/0x380 mm/slub.c:4171
 ptlock_alloc+0x20/0x70 mm/memory.c:7045
 ptlock_init include/linux/mm.h:2972 [inline]
 pagetable_pte_ctor include/linux/mm.h:2999 [inline]
 __pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
 pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41
 __pte_alloc+0x79/0x3c0 mm/memory.c:447
 do_anonymous_page mm/memory.c:4848 [inline]
 do_pte_missing mm/memory.c:4046 [inline]
 handle_pte_fault+0x4d4c/0x5ee0 mm/memory.c:5890
 __handle_mm_fault mm/memory.c:6033 [inline]
 handle_mm_fault+0x11f5/0x1d50 mm/memory.c:6202
 do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x2b9/0x8b0 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

Memory state around the buggy address:
 ffff88807b523f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807b523f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88807b524000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88807b524080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807b524100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


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=1328a6df980000
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=12ccaac4580000