Subject: [syzbot] KASAN: use-after-free Read in rdma_close

From: syzbot <[email-masked]>
Date: Sun, 25 Sep 2022 04:29:40 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    483fed3b5dc8 Add linux-next specific files for 20220921
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11450b0f080000
kernel config:  https://syzkaller.appspot.com/x/.config?x=849cb9f70f15b1ba
dashboard link: https://syzkaller.appspot.com/bug?extid=67d13108d855f451cafc
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11c18ce4880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12046b8c880000

Downloadable assets:
disk image: https://storage.googleapis.com/1cb3f4618323/disk-483fed3b.raw.xz
vmlinux: https://storage.googleapis.com/cc02cb30b495/vmlinux-483fed3b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

==================================================================
BUG: KASAN: use-after-free in rdma_close+0xaf/0xc0 net/9p/trans_rdma.c:555
Read of size 8 at addr ffff888016c73408 by task syz-executor151/3608

CPU: 0 PID: 3608 Comm: syz-executor151 Not tainted 6.0.0-rc6-next-20220921-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15e/0x45d mm/kasan/report.c:395
 kasan_report+0xbb/0x1f0 mm/kasan/report.c:495
 rdma_close+0xaf/0xc0 net/9p/trans_rdma.c:555
 p9_client_destroy+0xbe/0x370 net/9p/client.c:1040
 p9_client_create+0x728/0xf20 net/9p/client.c:1027
 v9fs_session_init+0x1e2/0x1810 fs/9p/v9fs.c:408
 v9fs_mount+0xba/0xc90 fs/9p/vfs_super.c:126
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1530
 do_new_mount fs/namespace.c:3040 [inline]
 path_mount+0x1326/0x1e20 fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f9a65969039
Code: 28 c3 e8 5a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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:00007ffda4b921e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffda4b921f8 RCX: 00007f9a65969039
RDX: 0000000020000080 RSI: 0000000020000040 RDI: 0000000020000000
RBP: 00007ffda4b921f0 R08: 00000000200000c0 R09: 00007f9a65927300
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 3608:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45
 kasan_set_track+0x21/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:371 [inline]
 ____kasan_kmalloc mm/kasan/common.c:330 [inline]
 __kasan_kmalloc+0xa1/0xb0 mm/kasan/common.c:380
 kmalloc include/linux/slab.h:559 [inline]
 kzalloc include/linux/slab.h:695 [inline]
 alloc_rdma net/9p/trans_rdma.c:567 [inline]
 rdma_create_trans+0x24f/0x13d0 net/9p/trans_rdma.c:644
 p9_client_create+0x7ef/0xf20 net/9p/client.c:992
 v9fs_session_init+0x1e2/0x1810 fs/9p/v9fs.c:408
 v9fs_mount+0xba/0xc90 fs/9p/vfs_super.c:126
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1530
 do_new_mount fs/namespace.c:3040 [inline]
 path_mount+0x1326/0x1e20 fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 3608:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45
 kasan_set_track+0x21/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2a/0x40 mm/kasan/generic.c:511
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1669 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1695
 slab_free mm/slub.c:3599 [inline]
 __kmem_cache_free+0xab/0x3b0 mm/slub.c:3612
 rdma_destroy_trans+0x196/0x210 net/9p/trans_rdma.c:380
 rdma_create_trans+0x1076/0x13d0 net/9p/trans_rdma.c:735
 p9_client_create+0x7ef/0xf20 net/9p/client.c:992
 v9fs_session_init+0x1e2/0x1810 fs/9p/v9fs.c:408
 v9fs_mount+0xba/0xc90 fs/9p/vfs_super.c:126
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1530
 do_new_mount fs/namespace.c:3040 [inline]
 path_mount+0x1326/0x1e20 fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888016c73400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
 512-byte region [ffff888016c73400, ffff888016c73600)

The buggy address belongs to the physical page:
page:ffffea00005b1c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16c70
head:ffffea00005b1c00 order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffff888011841c80 dead000080100010 0000000000000000
raw: 0000000000000000 dead000000000001 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 2303057531, free_ts 0
 prep_new_page mm/page_alloc.c:2538 [inline]
 get_page_from_freelist+0x1092/0x2d20 mm/page_alloc.c:4286
 __alloc_pages+0x1c7/0x5a0 mm/page_alloc.c:5545
 alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2113
 alloc_pages+0x22f/0x270 mm/mempolicy.c:2275
 alloc_slab_page mm/slub.c:1739 [inline]
 allocate_slab+0x213/0x300 mm/slub.c:1884
 new_slab mm/slub.c:1937 [inline]
 ___slab_alloc+0xac1/0x1430 mm/slub.c:3119
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3217
 slab_alloc_node mm/slub.c:3302 [inline]
 __kmem_cache_alloc_node+0x18a/0x3d0 mm/slub.c:3375
 __do_kmalloc_node mm/slab_common.c:933 [inline]
 __kmalloc+0x44/0xc0 mm/slab_common.c:947
 kmalloc include/linux/slab.h:564 [inline]
 kzalloc include/linux/slab.h:695 [inline]
 alloc_workqueue+0x14b/0x1020 kernel/workqueue.c:4314
 padata_alloc+0xc8/0x4d0 kernel/padata.c:984
 pcrypt_init_padata+0x1b/0xf5 crypto/pcrypt.c:323
 pcrypt_init+0x70/0xef crypto/pcrypt.c:348
 do_one_initcall+0x13d/0x780 init/main.c:1307
 do_initcall_level init/main.c:1382 [inline]
 do_initcalls init/main.c:1398 [inline]
 do_basic_setup init/main.c:1417 [inline]
 kernel_init_freeable+0x6ff/0x788 init/main.c:1637
 kernel_init+0x1a/0x1d0 init/main.c:1525
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888016c73300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888016c73380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888016c73400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888016c73480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888016c73500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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 [email-masked].

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