syzbot


KASAN: slab-use-after-free Read in p9_fid_destroy

Status: upstream: reported on 2024/03/07 08:14
Subsystems: v9fs
[Documentation on labels]
Reported-by: syzbot+d7c7a495a5e466c031b6@syzkaller.appspotmail.com
First crash: 44d, last: 44d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [v9fs?] KASAN: slab-use-after-free Read in p9_fid_destroy 0 (1) 2024/03/07 08:14

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in p9_fid_destroy+0xb5/0xd0 net/9p/client.c:884
Read of size 8 at addr ffff888064295880 by task kworker/u16:0/11

CPU: 0 PID: 11 Comm: kworker/u16:0 Not tainted 6.8.0-rc6-syzkaller-00250-g04b8076df253 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: events_unbound v9fs_upload_to_server_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc4/0x620 mm/kasan/report.c:488
 kasan_report+0xda/0x110 mm/kasan/report.c:601
 p9_fid_destroy+0xb5/0xd0 net/9p/client.c:884
 p9_client_clunk+0x12a/0x170 net/9p/client.c:1456
 p9_fid_put include/net/9p/client.h:278 [inline]
 v9fs_free_request+0xdc/0x110 fs/9p/vfs_addr.c:128
 netfs_free_request+0x225/0x670 fs/netfs/objects.c:97
 netfs_put_request+0x19b/0x1f0 fs/netfs/objects.c:130
 netfs_free_subrequest fs/netfs/objects.c:178 [inline]
 netfs_put_subrequest+0x3be/0x600 fs/netfs/objects.c:192
 v9fs_upload_to_server fs/9p/vfs_addr.c:36 [inline]
 v9fs_upload_to_server_worker+0x182/0x360 fs/9p/vfs_addr.c:44
 process_one_work+0x889/0x15e0 kernel/workqueue.c:2633
 process_scheduled_works kernel/workqueue.c:2706 [inline]
 worker_thread+0x8b9/0x12a0 kernel/workqueue.c:2787
 kthread+0x2c6/0x3b0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243
 </TASK>

Allocated by task 14429:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387
 kmalloc include/linux/slab.h:590 [inline]
 kzalloc include/linux/slab.h:711 [inline]
 p9_fid_create+0x45/0x470 net/9p/client.c:853
 p9_client_walk+0xc7/0x550 net/9p/client.c:1154
 clone_fid fs/9p/fid.h:23 [inline]
 v9fs_fid_clone fs/9p/fid.h:33 [inline]
 v9fs_file_open+0x623/0xc30 fs/9p/vfs_file.c:56
 do_dentry_open+0x8da/0x18c0 fs/open.c:953
 do_open fs/namei.c:3645 [inline]
 path_openat+0x1e00/0x29a0 fs/namei.c:3802
 do_filp_open+0x1de/0x440 fs/namei.c:3829
 do_sys_openat2+0x17a/0x1e0 fs/open.c:1404
 do_sys_open fs/open.c:1419 [inline]
 __do_sys_openat fs/open.c:1435 [inline]
 __se_sys_openat fs/open.c:1430 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1430
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6f/0x77

Freed by task 18115:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:589
 poison_slab_object mm/kasan/common.c:240 [inline]
 __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2121 [inline]
 slab_free mm/slub.c:4299 [inline]
 kfree+0x124/0x370 mm/slub.c:4409
 p9_client_destroy+0x14c/0x480 net/9p/client.c:1070
 v9fs_session_close+0x49/0x2d0 fs/9p/v9fs.c:506
 v9fs_kill_super+0x4d/0xa0 fs/9p/vfs_super.c:223
 deactivate_locked_super+0xbe/0x1a0 fs/super.c:472
 deactivate_super+0xde/0x100 fs/super.c:505
 cleanup_mnt+0x222/0x450 fs/namespace.c:1267
 task_work_run+0x14f/0x250 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:108 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
 syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:212
 do_syscall_64+0xe5/0x270 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x6f/0x77

The buggy address belongs to the object at ffff888064295880
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of
 freed 96-byte region [ffff888064295880, ffff8880642958e0)

The buggy address belongs to the physical page:
page:ffffea000190a540 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x64295
ksm flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888014c42780 ffffea0000c8c240 dead000000000007
raw: 0000000000000000 0000000000200020 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 0x112c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 10902, tgid 10901 (syz-executor.3), ts 360371748345, free_ts 360348940469
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1533
 prep_new_page mm/page_alloc.c:1540 [inline]
 get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3311
 __alloc_pages+0x22f/0x2440 mm/page_alloc.c:4567
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page mm/slub.c:2190 [inline]
 allocate_slab mm/slub.c:2354 [inline]
 new_slab+0xcc/0x3a0 mm/slub.c:2407
 ___slab_alloc+0x4af/0x19a0 mm/slub.c:3540
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3625
 __slab_alloc_node mm/slub.c:3678 [inline]
 slab_alloc_node mm/slub.c:3850 [inline]
 __do_kmalloc_node mm/slub.c:3980 [inline]
 __kmalloc+0x3b8/0x440 mm/slub.c:3994
 kmalloc_array include/linux/slab.h:627 [inline]
 kcalloc include/linux/slab.h:658 [inline]
 ext4_find_extent+0x95c/0xce0 fs/ext4/extents.c:914
 ext4_ext_map_blocks+0x26b/0x5bb0 fs/ext4/extents.c:4143
 ext4_map_blocks+0x61d/0x17d0 fs/ext4/inode.c:623
 ext4_iomap_alloc fs/ext4/inode.c:3318 [inline]
 ext4_iomap_begin+0x472/0x7d0 fs/ext4/inode.c:3368
 iomap_iter+0x48b/0xff0 fs/iomap/iter.c:91
 __iomap_dio_rw+0x6c4/0x1bd0 fs/iomap/direct-io.c:658
 iomap_dio_rw+0x40/0xa0 fs/iomap/direct-io.c:748
 ext4_dio_write_iter fs/ext4/file.c:577 [inline]
 ext4_file_write_iter+0x12c6/0x1960 fs/ext4/file.c:696
 call_write_iter include/linux/fs.h:2087 [inline]
 iter_file_splice_write+0x908/0x10b0 fs/splice.c:743
page last free pid 5164 tgid 5164 stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1140 [inline]
 free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2346
 free_unref_page+0x33/0x3c0 mm/page_alloc.c:2486
 skb_free_frag include/linux/skbuff.h:3270 [inline]
 skb_free_head+0xa6/0x1b0 net/core/skbuff.c:996
 skb_release_data+0x5c0/0x880 net/core/skbuff.c:1028
 skb_release_all net/core/skbuff.c:1094 [inline]
 __kfree_skb+0x51/0x70 net/core/skbuff.c:1108
 tcp_rcv_established+0xd72/0x20f0 net/ipv4/tcp_input.c:6080
 tcp_v4_do_rcv+0x6ab/0xa50 net/ipv4/tcp_ipv4.c:1906
 sk_backlog_rcv include/net/sock.h:1092 [inline]
 __release_sock+0x31b/0x400 net/core/sock.c:2972
 release_sock+0x5a/0x220 net/core/sock.c:3538
 tcp_sendmsg+0x38/0x50 net/ipv4/tcp.c:1342
 inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:850
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 sock_write_iter+0x4b8/0x5c0 net/socket.c:1160
 call_write_iter include/linux/fs.h:2087 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x6de/0x1110 fs/read_write.c:590
 ksys_write+0x1f8/0x260 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6f/0x77

Memory state around the buggy address:
 ffff888064295780: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff888064295800: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff888064295880: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                   ^
 ffff888064295900: 00 00 00 00 00 00 00 00 03 fc fc fc fc fc fc fc
 ffff888064295980: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/03 06:06 upstream 04b8076df253 25905f5d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-use-after-free Read in p9_fid_destroy
* Struck through repros no longer work on HEAD.