Re: [syzbot] [jfs?] KASAN: slab-out-of-bounds Write in diWrite

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-out-of-bounds Read in jfs_readdir

loop0: detected capacity change from 0 to 32768
lv: ffffc900028520b0 offset:0 diWrite
lv: ffffc900028520b2 offset:6 diWrite
lv: ffffc900028520b4 offset:0 diWrite
lv: ffffc900028520b6 offset:0 diWrite
==================================================================
BUG: KASAN: slab-out-of-bounds in jfs_readdir+0x1b79/0x4660 fs/jfs/jfs_dtree.c:2894
Read of size 1 at addr ffff888076df3d15 by task syz-executor.0/5492

CPU: 0 PID: 5492 Comm: syz-executor.0 Not tainted 6.9.0-rc5-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
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
 jfs_readdir+0x1b79/0x4660 fs/jfs/jfs_dtree.c:2894
 wrap_directory_iterator+0x94/0xe0 fs/readdir.c:67
 iterate_dir+0x539/0x6f0 fs/readdir.c:110
 __do_sys_getdents64 fs/readdir.c:409 [inline]
 __se_sys_getdents64+0x20d/0x4f0 fs/readdir.c:394
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8966e7dea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f89669ff0c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f8966fabf80 RCX: 00007f8966e7dea9
RDX: 000000000000005d RSI: 00000000200002c0 RDI: 0000000000000005
RBP: 00007f8966eca4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f8966fabf80 R15: 00007ffe3b2048e8
 </TASK>

The buggy address belongs to the object at ffff888076df3780
 which belongs to the cache jfs_ip of size 2240
The buggy address is located 1429 bytes inside of
 allocated 2240-byte region [ffff888076df3780, ffff888076df4040)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x76df0
head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88802aef9f01
flags: 0xfff80000000840(slab|head|node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000840 ffff8880197418c0 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800d000d 00000001ffffffff ffff88802aef9f01
head: 00fff80000000840 ffff8880197418c0 dead000000000122 0000000000000000
head: 0000000000000000 00000000800d000d 00000001ffffffff ffff88802aef9f01
head: 00fff80000000003 ffffea0001db7c01 dead000000000122 00000000ffffffff
head: 0000000800000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0x1d2050(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 5490, tgid 1905245577 (syz-executor.0), ts 5492, free_ts 87323640300
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
 __alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page+0x5f/0x160 mm/slub.c:2175
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0x84/0x2f0 mm/slub.c:2391
 ___slab_alloc+0xc73/0x1260 mm/slub.c:3525
 __slab_alloc mm/slub.c:3610 [inline]
 __slab_alloc_node mm/slub.c:3663 [inline]
 slab_alloc_node mm/slub.c:3835 [inline]
 kmem_cache_alloc_lru+0x253/0x350 mm/slub.c:3864
 alloc_inode_sb include/linux/fs.h:3091 [inline]
 jfs_alloc_inode+0x28/0x70 fs/jfs/super.c:105
 alloc_inode fs/inode.c:261 [inline]
 new_inode_pseudo+0x69/0x1e0 fs/inode.c:1007
 new_inode+0x22/0x1d0 fs/inode.c:1033
 jfs_fill_super+0x408/0xc50 fs/jfs/super.c:544
 mount_bdev+0x20a/0x2d0 fs/super.c:1658
 legacy_get_tree+0xee/0x190 fs/fs_context.c:662
 vfs_get_tree+0x90/0x2a0 fs/super.c:1779
 do_new_mount+0x2be/0xb40 fs/namespace.c:3352
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
page last free pid 4525 tgid 4525 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1141 [inline]
 free_unref_page_prepare+0x97b/0xaa0 mm/page_alloc.c:2347
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
 discard_slab mm/slub.c:2437 [inline]
 __put_partials+0xeb/0x130 mm/slub.c:2906
 put_cpu_partial+0x17c/0x250 mm/slub.c:2981
 __slab_free+0x2ea/0x3d0 mm/slub.c:4151
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x5e/0xc0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3798 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 kmem_cache_alloc+0x174/0x340 mm/slub.c:3852
 kmem_cache_zalloc include/linux/slab.h:739 [inline]
 lsm_file_alloc security/security.c:649 [inline]
 security_file_alloc+0x28/0x130 security/security.c:2709
 init_file+0x99/0x200 fs/file_table.c:152
 alloc_empty_file+0xb8/0x1d0 fs/file_table.c:206
 path_openat+0xfb/0x3240 fs/namei.c:3785
 do_filp_open+0x235/0x490 fs/namei.c:3826
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
 do_sys_open fs/open.c:1421 [inline]
 __do_sys_openat fs/open.c:1437 [inline]
 __se_sys_openat fs/open.c:1432 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1432

Memory state around the buggy address:
 ffff888076df3c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888076df3c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888076df3d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff888076df3d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888076df3e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


Tested on:

commit:         ed30a4a5 Linux 6.9-rc5
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=12ba37b8980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5a05c230e142f2bc
dashboard link: https://syzkaller.appspot.com/bug?extid=aa6df9d3b383bf5f047f
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12a532e0980000