Message-ID: <0000000000005d2c82061c69e8ca@google.com>
Date: Thu, 04 Jul 2024 04:04:15 -0700
From: syzbot <syzbot+7efd59a5a532c57037e6@...kaller.appspotmail.com>
To: agruenba@...hat.com, gfs2@...ts.linux.dev, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [gfs2?] KASAN: stack-out-of-bounds Read in gfs2_dump_glock

syzbot has found a reproducer for the following issue on:

HEAD commit:    795c58e4c7fc Merge tag 'trace-v6.10-rc6' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16418635980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1ace69f521989b1f
dashboard link: https://syzkaller.appspot.com/bug?extid=7efd59a5a532c57037e6
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=15e82849980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11b55181980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/947727e7be17/disk-795c58e4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8898920020bb/vmlinux-795c58e4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9aed6052df98/bzImage-795c58e4.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/7bee2c9df91a/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7efd59a5a532c57037e6@...kaller.appspotmail.com

gfs2: fsid=syz:syz.0:  H: s:SH f:H e:0 p:5123 [syz-executor201] iterate_dir+0x57a/0x810 fs/readdir.c:110
==================================================================
BUG: KASAN: stack-out-of-bounds in gfs2_dump_glock+0x15b1/0x1bb0
Read of size 8 at addr ffffc900034a7ca0 by task syz-executor201/5125

CPU: 0 PID: 5125 Comm: syz-executor201 Not tainted 6.10.0-rc6-syzkaller-00069-g795c58e4c7fc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
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
 gfs2_dump_glock+0x15b1/0x1bb0
 gfs2_consist_inode_i+0xf5/0x110 fs/gfs2/util.c:457
 gfs2_dirent_scan+0x52b/0x670
 gfs2_dirent_search+0x30e/0x8c0 fs/gfs2/dir.c:853
 gfs2_dir_search+0xb2/0x2f0 fs/gfs2/dir.c:1653
 gfs2_lookupi+0x461/0x5e0 fs/gfs2/inode.c:340
 __gfs2_lookup+0xa4/0x280 fs/gfs2/inode.c:896
 __lookup_slow+0x28c/0x3f0 fs/namei.c:1692
 lookup_slow+0x53/0x70 fs/namei.c:1709
 walk_component fs/namei.c:2004 [inline]
 link_path_walk+0x9ea/0xea0 fs/namei.c:2331
 path_parentat fs/namei.c:2540 [inline]
 __filename_parentat+0x263/0x6f0 fs/namei.c:2564
 filename_parentat fs/namei.c:2582 [inline]
 filename_create+0xf6/0x540 fs/namei.c:3887
 do_mknodat+0x18b/0x5b0 fs/namei.c:4052
 __do_sys_mknod fs/namei.c:4098 [inline]
 __se_sys_mknod fs/namei.c:4096 [inline]
 __x64_sys_mknod+0x8e/0xa0 fs/namei.c:4096
 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: 0033:0x7fc9a7de9779
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 1f 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:00007fc9a7d75168 EFLAGS: 00000246 ORIG_RAX: 0000000000000085
RAX: ffffffffffffffda RBX: 00007fc9a7e7d6d8 RCX: 00007fc9a7de9779
RDX: 0000000000000701 RSI: 0000000000000000 RDI: 0000000020000680
RBP: 00007fc9a7e7d6d0 R08: 00007ffc076d7ae7 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc9a7e7d6dc
R13: 000000000000006e R14: 00007ffc076d7a00 R15: 00007ffc076d7ae8
 </TASK>

The buggy address belongs to the virtual mapping at
 [ffffc900034a0000, ffffc900034a9000) created by:
 copy_process+0x5d1/0x3dc0 kernel/fork.c:2220

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802c96fd80 pfn:0x2c96f
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff88802c96fd80 0000000000000000 00000001ffffffff 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 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_ZERO), pid 5106, tgid 5106 (syz-executor201), ts 62007196465, free_ts 61954421151
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1473
 prep_new_page mm/page_alloc.c:1481 [inline]
 get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3425
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4683
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
 vm_area_alloc_pages mm/vmalloc.c:3575 [inline]
 __vmalloc_area_node mm/vmalloc.c:3651 [inline]
 __vmalloc_node_range_noprof+0x971/0x1460 mm/vmalloc.c:3832
 alloc_thread_stack_node kernel/fork.c:309 [inline]
 dup_task_struct+0x444/0x8c0 kernel/fork.c:1115
 copy_process+0x5d1/0x3dc0 kernel/fork.c:2220
 kernel_clone+0x223/0x870 kernel/fork.c:2797
 __do_sys_clone3 kernel/fork.c:3098 [inline]
 __se_sys_clone3+0x2cb/0x350 kernel/fork.c:3082
 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
page last free pid 5074 tgid 5074 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1093 [inline]
 free_unref_page+0xd19/0xea0 mm/page_alloc.c:2588
 discard_slab mm/slub.c:2527 [inline]
 __put_partials+0xeb/0x130 mm/slub.c:2995
 put_cpu_partial+0x17c/0x250 mm/slub.c:3070
 __slab_free+0x2ea/0x3d0 mm/slub.c:4308
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9e/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:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3940 [inline]
 slab_alloc_node mm/slub.c:4002 [inline]
 kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4045
 __alloc_skb+0x1c3/0x440 net/core/skbuff.c:656
 netlink_sendmsg+0x631/0xcb0 net/netlink/af_netlink.c:1880
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2585
 ___sys_sendmsg net/socket.c:2639 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2668
 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:
 ffffc900034a7b80: 00 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc900034a7c00: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00
>ffffc900034a7c80: 00 f3 f3 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
                               ^
 ffffc900034a7d00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
 ffffc900034a7d80: 04 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

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