syzbot


KASAN: slab-use-after-free Write in v9fs_free_request

Status: upstream: reported on 2024/05/12 19:42
Subsystems: v9fs
[Documentation on labels]
Reported-by: syzbot+df038d463cca332e8414@syzkaller.appspotmail.com
Fix commit: f89ea63f1c65 netfs, 9p: Fix race between umount and async request completion
Patched on: [ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-linux-next-kasan-gce-root ci2-upstream-fs ci2-upstream-kcsan-gce], missing on: [ci-qemu2-riscv64 ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-kmsan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-net-next-test-gce ci2-upstream-usb]
First crash: 44d, last: 3d12h
Discussions (5)
Title Replies (including bot) Last reply
[PATCH v3] netfs, 9p: Fix race between umount and async request completion 2 (2) 2024/05/27 11:09
[syzbot] [v9fs?] KASAN: slab-use-after-free Read in p9_fid_destroy 11 (21) 2024/05/23 20:57
[PATCH v2] netfs, 9p: Fix race between umount and async request completion 1 (1) 2024/05/23 15:25
[syzbot] [v9fs?] KASAN: slab-use-after-free Write in v9fs_free_request 4 (6) 2024/05/22 21:09
Re: [syzbot] [v9fs?] KASAN: slab-use-after-free Write in v9fs_free_request 1 (1) 2024/05/13 11:50

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline]
BUG: KASAN: slab-use-after-free in __refcount_sub_and_test include/linux/refcount.h:264 [inline]
BUG: KASAN: slab-use-after-free in __refcount_dec_and_test include/linux/refcount.h:307 [inline]
BUG: KASAN: slab-use-after-free in refcount_dec_and_test include/linux/refcount.h:325 [inline]
BUG: KASAN: slab-use-after-free in p9_fid_put include/net/9p/client.h:277 [inline]
BUG: KASAN: slab-use-after-free in v9fs_free_request+0x5f/0xe0 fs/9p/vfs_addr.c:138
Write of size 4 at addr ffff88801cf6d50c by task kworker/u8:1/12

CPU: 0 PID: 12 Comm: kworker/u8:1 Not tainted 6.9.0-syzkaller-12277-g56fb6f92854f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Workqueue: events_unbound netfs_write_collection_worker
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
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline]
 __refcount_sub_and_test include/linux/refcount.h:264 [inline]
 __refcount_dec_and_test include/linux/refcount.h:307 [inline]
 refcount_dec_and_test include/linux/refcount.h:325 [inline]
 p9_fid_put include/net/9p/client.h:277 [inline]
 v9fs_free_request+0x5f/0xe0 fs/9p/vfs_addr.c:138
 netfs_free_request+0x246/0x5e0 fs/netfs/objects.c:133
 netfs_write_collection_worker+0x507c/0x5640 fs/netfs/write_collect.c:701
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2e/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 13442:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 kmalloc_trace_noprof+0x19c/0x2c0 mm/slub.c:4152
 kmalloc_noprof include/linux/slab.h:660 [inline]
 kzalloc_noprof include/linux/slab.h:778 [inline]
 p9_fid_create+0x4f/0x230 net/9p/client.c:854
 p9_client_walk+0x103/0x690 net/9p/client.c:1155
 clone_fid fs/9p/fid.h:23 [inline]
 v9fs_fid_clone fs/9p/fid.h:33 [inline]
 v9fs_file_open+0x285/0xa60 fs/9p/vfs_file.c:56
 do_dentry_open+0x95c/0x1720 fs/open.c:955
 do_open fs/namei.c:3650 [inline]
 path_openat+0x289f/0x3280 fs/namei.c:3807
 do_filp_open+0x235/0x490 fs/namei.c:3834
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1405
 do_sys_open fs/open.c:1420 [inline]
 __do_sys_creat fs/open.c:1496 [inline]
 __se_sys_creat fs/open.c:1490 [inline]
 __x64_sys_creat+0x123/0x170 fs/open.c:1490
 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

Freed by task 9127:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2195 [inline]
 slab_free mm/slub.c:4436 [inline]
 kfree+0x149/0x360 mm/slub.c:4557
 p9_fid_destroy net/9p/client.c:890 [inline]
 p9_client_destroy+0x1fb/0x660 net/9p/client.c:1071
 v9fs_session_close+0x51/0x210 fs/9p/v9fs.c:506
 v9fs_kill_super+0x5c/0x90 fs/9p/vfs_super.c:196
 deactivate_locked_super+0xc6/0x130 fs/super.c:473
 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1267
 task_work_run+0x251/0x310 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:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88801cf6d500
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 12 bytes inside of
 freed 96-byte region [ffff88801cf6d500, ffff88801cf6d560)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1cf6d
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 00fff00000000000 ffff888015041280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000200020 00000001ffffefff 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 0x152c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 5229, tgid 5229 (syz-executor.2), ts 88392341107, free_ts 88340128533
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1468
 prep_new_page mm/page_alloc.c:1476 [inline]
 get_page_from_freelist+0x2e2d/0x2ee0 mm/page_alloc.c:3402
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4660
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page+0x5f/0x120 mm/slub.c:2264
 allocate_slab+0x5a/0x2e0 mm/slub.c:2427
 new_slab mm/slub.c:2480 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3666
 __slab_alloc+0x58/0xa0 mm/slub.c:3756
 __slab_alloc_node mm/slub.c:3809 [inline]
 slab_alloc_node mm/slub.c:3988 [inline]
 __do_kmalloc_node mm/slub.c:4120 [inline]
 __kmalloc_noprof+0x257/0x400 mm/slub.c:4134
 kmalloc_noprof include/linux/slab.h:664 [inline]
 kzalloc_noprof include/linux/slab.h:778 [inline]
 tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
 tomoyo_encode+0x26f/0x540 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x59e/0x5e0 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x2b7/0x740 security/tomoyo/file.c:822
 tomoyo_path_symlink+0xde/0x120 security/tomoyo/tomoyo.c:212
 security_path_symlink+0xe5/0x140 security/security.c:1876
 do_symlinkat+0x136/0x3a0 fs/namei.c:4513
 __do_sys_symlinkat fs/namei.c:4531 [inline]
 __se_sys_symlinkat fs/namei.c:4528 [inline]
 __x64_sys_symlinkat+0x99/0xb0 fs/namei.c:4528
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
page last free pid 4540 tgid 4540 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1088 [inline]
 free_unref_page+0xd22/0xea0 mm/page_alloc.c:2565
 discard_slab mm/slub.c:2526 [inline]
 __put_partials+0xeb/0x130 mm/slub.c:2994
 put_cpu_partial+0x17c/0x250 mm/slub.c:3069
 __slab_free+0x2ea/0x3d0 mm/slub.c:4306
 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:4000 [inline]
 kmalloc_trace_noprof+0x132/0x2c0 mm/slub.c:4147
 kmalloc_noprof include/linux/slab.h:660 [inline]
 kzalloc_noprof include/linux/slab.h:778 [inline]
 kernfs_fop_open+0x3e0/0xd10 fs/kernfs/file.c:623
 do_dentry_open+0x95c/0x1720 fs/open.c:955
 do_open fs/namei.c:3650 [inline]
 path_openat+0x289f/0x3280 fs/namei.c:3807
 do_filp_open+0x235/0x490 fs/namei.c:3834
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1405
 do_sys_open fs/open.c:1420 [inline]
 __do_sys_openat fs/open.c:1436 [inline]
 __se_sys_openat fs/open.c:1431 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1431
 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:
 ffff88801cf6d400: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
 ffff88801cf6d480: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff88801cf6d500: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                      ^
 ffff88801cf6d580: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
 ffff88801cf6d600: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/05/25 20:23 upstream 56fb6f92854f a10a183e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-use-after-free Write in v9fs_free_request
2024/05/13 21:41 upstream cd97950cbcab fdb4c10c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Write in v9fs_free_request
2024/05/12 19:41 upstream ba16c1cf11c9 9026e142 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-use-after-free Write in v9fs_free_request
2024/04/23 16:04 upstream 71b1543c83d6 21339d7b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Write in v9fs_free_request
2024/05/01 20:42 upstream 0106679839f7 3ba885bc .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-use-after-free Write in v9fs_free_request
2024/05/27 04:13 upstream 1613e604df0c c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-use-after-free Write in v9fs_free_request
2024/04/16 09:38 upstream 96fca68c4fbf 0d592ce4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-use-after-free Write in v9fs_free_request
2024/05/14 09:14 linux-next 26dd54d03cd9 fdb4c10c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Write in v9fs_free_request
2024/04/28 23:04 linux-next bb7a2467e6be 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Write in v9fs_free_request
* Struck through repros no longer work on HEAD.