Date:   Wed, 5 Oct 2022 11:10:30 +0200
From:   Dmitry Vyukov <dvyukov@...gle.com>
To:     syzbot <syzbot+cfd8fb005ec6f019dd45@...kaller.appspotmail.com>
Cc:     jfs-discussion@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
        shaggy@...nel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] KASAN: slab-out-of-bounds Read in ea_get

On Tue, 4 Oct 2022 at 23:00, syzbot
<syzbot+cfd8fb005ec6f019dd45@...kaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    a5088ee7251e Merge tag 'thermal-6.1-rc1' of git://git.kern..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1211c8cc880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=8b8947ea4cc7fb5d
> dashboard link: https://syzkaller.appspot.com/bug?extid=cfd8fb005ec6f019dd45
> compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13441df4880000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10133a82880000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/e107029667b6/disk-a5088ee7.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/8e538d6b0960/vmlinux-a5088ee7.xz
> mounted in repro: https://storage.googleapis.com/syzbot-assets/dc07001c8be9/mount_0.gz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+cfd8fb005ec6f019dd45@...kaller.appspotmail.com
>
> ffff888073928860: 00 02 00 00 00 00 00 00 68 88 92 73 80 88 ff ff  ........h..s....
> ffff888073928870: 68 88 92 73 80 88 ff ff 00 00 00 00 00 00 00 00  h..s............
> ffff888073928880: 80 88 92 73 80 88 ff ff 80 88 92 73 80 88 ff ff  ...s.......s....
> ffff888073928890: 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
> ffff8880739288a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> ffff8880739288b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in hex_dump_to_buffer+0x72a/0xb80 lib/hexdump.c:193
> Read of size 1 at addr ffff8880739288c0 by task syz-executor200/3608
>
> CPU: 0 PID: 3608 Comm: syz-executor200 Not tainted 6.0.0-syzkaller-00372-ga5088ee7251e #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
>  print_address_description+0x65/0x4b0 mm/kasan/report.c:317
>  print_report+0x108/0x220 mm/kasan/report.c:433
>  kasan_report+0xfb/0x130 mm/kasan/report.c:495
>  hex_dump_to_buffer+0x72a/0xb80 lib/hexdump.c:193
>  print_hex_dump+0x13e/0x270 lib/hexdump.c:276

This is the same as:

#syz dup: KASAN: slab-out-of-bounds Read in hex_dump_to_buffer

https://syzkaller.appspot.com/bug?id=25e21194d00c9199ff645f8e82625559368f723b

>  ea_get+0xccc/0x1280 fs/jfs/xattr.c:561
>  __jfs_getxattr+0xd0/0x390 fs/jfs/xattr.c:807
>  __vfs_getxattr+0x3de/0x410 fs/xattr.c:411
>  smk_fetch+0xb0/0x140 security/smack/smack_lsm.c:295
>  smack_d_instantiate+0x5c4/0xa10 security/smack/smack_lsm.c:3410
>  security_d_instantiate+0xa5/0x100 security/security.c:2056
>  d_splice_alias+0x6e/0x3b0 fs/dcache.c:3155
>  jfs_lookup+0x2b9/0x400 fs/jfs/namei.c:1467
>  __lookup_slow+0x286/0x3e0 fs/namei.c:1685
>  lookup_slow+0x53/0x70 fs/namei.c:1702
>  walk_component+0x2e1/0x410 fs/namei.c:1993
>  lookup_last fs/namei.c:2450 [inline]
>  path_lookupat+0x17d/0x450 fs/namei.c:2474
>  do_o_path+0x91/0x230 fs/namei.c:3662
>  path_openat+0x2824/0x2e00 fs/namei.c:3684
>  do_filp_open+0x275/0x500 fs/namei.c:3718
>  do_sys_openat2+0x13b/0x500 fs/open.c:1313
>  do_sys_open fs/open.c:1329 [inline]
>  __do_sys_open fs/open.c:1337 [inline]
>  __se_sys_open fs/open.c:1333 [inline]
>  __x64_sys_open+0x221/0x270 fs/open.c:1333
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7f9104172109
> 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 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffc9f9e17b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
> RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007f9104172109
> RDX: 0000000000000000 RSI: 0000000000212041 RDI: 0000000020000040
> RBP: 00007f91041318d0 R08: 00005555570102c0 R09: 0000000000000000
> R10: 00007ffc9f9e1680 R11: 0000000000000246 R12: 00000000f8008000
> R13: 0000000000000000 R14: 00080000000000f8 R15: 0000000000000000
>  </TASK>
>
> Allocated by task 3608:
>  kasan_save_stack mm/kasan/common.c:38 [inline]
>  kasan_set_track mm/kasan/common.c:45 [inline]
>  set_alloc_info mm/kasan/common.c:437 [inline]
>  __kasan_slab_alloc+0xb2/0xe0 mm/kasan/common.c:470
>  kasan_slab_alloc include/linux/kasan.h:224 [inline]
>  slab_post_alloc_hook mm/slab.h:727 [inline]
>  slab_alloc_node mm/slub.c:3248 [inline]
>  slab_alloc mm/slub.c:3256 [inline]
>  __kmem_cache_alloc_lru mm/slub.c:3263 [inline]
>  kmem_cache_alloc_lru+0x175/0x2d0 mm/slub.c:3280
>  alloc_inode_sb include/linux/fs.h:3103 [inline]
>  jfs_alloc_inode+0x21/0x60 fs/jfs/super.c:105
>  alloc_inode fs/inode.c:260 [inline]
>  iget_locked+0x191/0x830 fs/inode.c:1287
>  jfs_iget+0x20/0x3b0 fs/jfs/inode.c:29
>  jfs_lookup+0x221/0x400 fs/jfs/namei.c:1462
>  __lookup_slow+0x286/0x3e0 fs/namei.c:1685
>  lookup_slow+0x53/0x70 fs/namei.c:1702
>  walk_component+0x2e1/0x410 fs/namei.c:1993
>  lookup_last fs/namei.c:2450 [inline]
>  path_lookupat+0x17d/0x450 fs/namei.c:2474
>  do_o_path+0x91/0x230 fs/namei.c:3662
>  path_openat+0x2824/0x2e00 fs/namei.c:3684
>  do_filp_open+0x275/0x500 fs/namei.c:3718
>  do_sys_openat2+0x13b/0x500 fs/open.c:1313
>  do_sys_open fs/open.c:1329 [inline]
>  __do_sys_open fs/open.c:1337 [inline]
>  __se_sys_open fs/open.c:1333 [inline]
>  __x64_sys_open+0x221/0x270 fs/open.c:1333
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> The buggy address belongs to the object at ffff888073928000
>  which belongs to the cache jfs_ip of size 2240
> The buggy address is located 0 bytes to the right of
>  2240-byte region [ffff888073928000, ffff8880739288c0)
>
> The buggy address belongs to the physical page:
> page:ffffea0001ce4a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x73928
> head:ffffea0001ce4a00 order:3 compound_mapcount:0 compound_pincount:0
> flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
> raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888146477c80
> raw: 0000000000000000 00000000800d000d 00000001ffffffff 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 0xd2050(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_RECLAIMABLE), pid 3608, tgid 3608 (syz-executor200), ts 50651788147, free_ts 11286970323
>  prep_new_page mm/page_alloc.c:2532 [inline]
>  get_page_from_freelist+0x72b/0x7a0 mm/page_alloc.c:4283
>  __alloc_pages+0x259/0x560 mm/page_alloc.c:5549
>  alloc_slab_page+0x70/0xf0 mm/slub.c:1829
>  allocate_slab+0x5e/0x520 mm/slub.c:1974
>  new_slab mm/slub.c:2034 [inline]
>  ___slab_alloc+0x42e/0xce0 mm/slub.c:3036
>  __slab_alloc mm/slub.c:3123 [inline]
>  slab_alloc_node mm/slub.c:3214 [inline]
>  slab_alloc mm/slub.c:3256 [inline]
>  __kmem_cache_alloc_lru mm/slub.c:3263 [inline]
>  kmem_cache_alloc_lru+0x225/0x2d0 mm/slub.c:3280
>  alloc_inode_sb include/linux/fs.h:3103 [inline]
>  jfs_alloc_inode+0x21/0x60 fs/jfs/super.c:105
>  alloc_inode fs/inode.c:260 [inline]
>  iget_locked+0x191/0x830 fs/inode.c:1287
>  jfs_iget+0x20/0x3b0 fs/jfs/inode.c:29
>  jfs_lookup+0x221/0x400 fs/jfs/namei.c:1462
>  __lookup_slow+0x286/0x3e0 fs/namei.c:1685
>  lookup_slow+0x53/0x70 fs/namei.c:1702
>  walk_component+0x2e1/0x410 fs/namei.c:1993
>  lookup_last fs/namei.c:2450 [inline]
>  path_lookupat+0x17d/0x450 fs/namei.c:2474
>  do_o_path+0x91/0x230 fs/namei.c:3662
>  path_openat+0x2824/0x2e00 fs/namei.c:3684
> page last free stack trace:
>  reset_page_owner include/linux/page_owner.h:24 [inline]
>  free_pages_prepare mm/page_alloc.c:1449 [inline]
>  free_pcp_prepare+0x812/0x900 mm/page_alloc.c:1499
>  free_unref_page_prepare mm/page_alloc.c:3380 [inline]
>  free_unref_page+0x7d/0x630 mm/page_alloc.c:3476
>  free_contig_range+0xa3/0x160 mm/page_alloc.c:9453
>  destroy_args+0xfe/0x971 mm/debug_vm_pgtable.c:1031
>  debug_vm_pgtable+0x454/0x4ad mm/debug_vm_pgtable.c:1354
>  do_one_initcall+0xbd/0x2b0 init/main.c:1296
>  do_initcall_level+0x168/0x218 init/main.c:1369
>  do_initcalls+0x4b/0x8c init/main.c:1385
>  kernel_init_freeable+0x43a/0x5c3 init/main.c:1623
>  kernel_init+0x19/0x2b0 init/main.c:1512
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
>
> Memory state around the buggy address:
>  ffff888073928780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>  ffff888073928800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffff888073928880: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>                                            ^
>  ffff888073928900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffff888073928980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@...glegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches
>
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