syzbot

 sign-in | mailing list | source | docs
🐞 Open [1413]
≡ Subsystems
🐞 Fixed [5827]
🐞 Invalid [14217]
⬇ Missing Backports [92]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
💬 Send us feedback

KASAN: slab-use-after-free Read in drm_atomic_helper_wait_for_vblanks (2)

Status: upstream: reported C repro on 2024/02/12 10:50
Subsystems: dri
[Documentation on labels]
Reported-by: syzbot+0f999d26a4fd79c3a23b@syzkaller.appspotmail.com
First crash: 283d, last: 8d12h
▶ ▼ Discussions (6)
Title Replies (including bot) Last reply
[syzbot] Monthly dri report (Nov 2024) 0 (1) 2024/11/14 08:59
[syzbot] Monthly dri report (Oct 2024) 0 (1) 2024/10/13 19:21
[syzbot] Monthly dri report (Mar 2024) 0 (1) 2024/03/05 11:09
[PATCH v2] drm/atomic-helpers: fix uaf in drm_atomic_helper_wait_for_vblanks 1 (1) 2024/02/15 15:12
[PATCH] drm/atomic-helpers: fix uaf in drm_atomic_helper_wait_for_vblanks 1 (1) 2024/02/15 13:02
[syzbot] [dri?] KASAN: slab-use-after-free Read in drm_atomic_helper_wait_for_vblanks (2) 5 (12) 2024/02/15 10:39
▶ ▼ Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in drm_atomic_helper_wait_for_vblanks dri 2 406d 499d 0/28 auto-obsoleted due to no activity on 2024/01/20 05:42
▶ ▼ Last patch testing requests (9)
Created Duration User Patch Repo Result
2024/10/02 08:37 12m retest repro upstream report log
2024/07/16 15:39 17m retest repro upstream report log
2024/05/07 15:00 16m retest repro upstream report log
2024/02/27 14:36 16m retest repro upstream report log
2024/02/15 10:15 23m eadavis@qq.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master OK log
2024/02/14 11:19 34m hdanton@sina.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master OK log
2024/02/14 07:02 23m hdanton@sina.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master error
2024/02/14 03:39 14m hdanton@sina.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master report log
2024/02/14 01:33 27m hdanton@sina.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master error

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in drm_atomic_helper_wait_for_vblanks.part.0+0x851/0x930 drivers/gpu/drm/drm_atomic_helper.c:1662
Read of size 1 at addr ffff888035333809 by task kworker/u32:1/12

CPU: 0 UID: 0 PID: 12 Comm: kworker/u32:1 Not tainted 6.12.0-rc7-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: events_unbound commit_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 drm_atomic_helper_wait_for_vblanks.part.0+0x851/0x930 drivers/gpu/drm/drm_atomic_helper.c:1662
 drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1658 [inline]
 drm_atomic_helper_commit_tail+0xcb/0xf0 drivers/gpu/drm/drm_atomic_helper.c:1758
 commit_tail+0x353/0x400 drivers/gpu/drm/drm_atomic_helper.c:1835
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 6825:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:878 [inline]
 drm_atomic_helper_crtc_duplicate_state+0x70/0xd0 drivers/gpu/drm/drm_atomic_state_helper.c:177
 drm_atomic_get_crtc_state+0x162/0x440 drivers/gpu/drm/drm_atomic.c:360
 page_flip_common+0x57/0x320 drivers/gpu/drm/drm_atomic_helper.c:3631
 drm_atomic_helper_page_flip+0xb6/0x180 drivers/gpu/drm/drm_atomic_helper.c:3692
 drm_mode_page_flip_ioctl+0x1044/0x1470 drivers/gpu/drm/drm_plane.c:1516
 drm_ioctl_kernel+0x1e6/0x3d0 drivers/gpu/drm/drm_ioctl.c:745
 drm_ioctl+0x5d6/0xc00 drivers/gpu/drm/drm_ioctl.c:842
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18f/0x220 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6825:
 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:579
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:2342 [inline]
 slab_free mm/slub.c:4579 [inline]
 kfree+0x14f/0x4b0 mm/slub.c:4727
 drm_atomic_state_default_clear+0x43c/0xe00 drivers/gpu/drm/drm_atomic.c:224
 drm_atomic_state_clear drivers/gpu/drm/drm_atomic.c:293 [inline]
 __drm_atomic_state_free+0x185/0x2b0 drivers/gpu/drm/drm_atomic.c:310
 kref_put include/linux/kref.h:65 [inline]
 drm_atomic_state_put include/drm/drm_atomic.h:538 [inline]
 drm_client_modeset_commit_atomic+0x6c5/0x800 drivers/gpu/drm/drm_client_modeset.c:1074
 drm_client_modeset_commit_locked+0x14d/0x580 drivers/gpu/drm/drm_client_modeset.c:1171
 drm_client_modeset_commit+0x4f/0x80 drivers/gpu/drm/drm_client_modeset.c:1197
 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:237 [inline]
 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:216 [inline]
 drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:264 [inline]
 drm_fb_helper_lastclose+0xc7/0x160 drivers/gpu/drm/drm_fb_helper.c:2003
 drm_fbdev_shmem_client_restore+0x2c/0x40 drivers/gpu/drm/drm_fbdev_shmem.c:229
 drm_client_dev_restore+0x188/0x2a0 drivers/gpu/drm/drm_client.c:260
 drm_lastclose drivers/gpu/drm/drm_file.c:391 [inline]
 drm_release+0x2c2/0x360 drivers/gpu/drm/drm_file.c:424
 __fput+0x3f6/0xb60 fs/file_table.c:431
 __fput_sync+0x45/0x50 fs/file_table.c:516
 __do_sys_close fs/open.c:1567 [inline]
 __se_sys_close fs/open.c:1552 [inline]
 __x64_sys_close+0x86/0x100 fs/open.c:1552
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888035333800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 9 bytes inside of
 freed 512-byte region [ffff888035333800, ffff888035333a00)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x35330
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b042c80 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
head: 00fff00000000040 ffff88801b042c80 dead000000000122 0000000000000000
head: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
head: 00fff00000000002 ffffea0000d4cc01 ffffffffffffffff 0000000000000000
head: 0000000000000004 0000000000000000 00000000ffffffff 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 6819, tgid 6819 (syz-executor295), ts 49983907780, free_ts 49305885986
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1541
 prep_new_page mm/page_alloc.c:1549 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3459
 __alloc_pages_noprof+0x223/0x25a0 mm/page_alloc.c:4735
 alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265
 alloc_slab_page mm/slub.c:2412 [inline]
 allocate_slab mm/slub.c:2578 [inline]
 new_slab+0x2c9/0x410 mm/slub.c:2631
 ___slab_alloc+0xdac/0x1880 mm/slub.c:3818
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3908
 __slab_alloc_node mm/slub.c:3961 [inline]
 slab_alloc_node mm/slub.c:4122 [inline]
 __kmalloc_cache_noprof+0x2b4/0x300 mm/slub.c:4290
 kmalloc_noprof include/linux/slab.h:878 [inline]
 kzalloc_noprof include/linux/slab.h:1014 [inline]
 drm_atomic_helper_setup_commit+0x633/0x15e0 drivers/gpu/drm/drm_atomic_helper.c:2288
 drm_atomic_helper_commit+0xa9/0x380 drivers/gpu/drm/drm_atomic_helper.c:2023
 drm_atomic_nonblocking_commit+0x12c/0x190 drivers/gpu/drm/drm_atomic.c:1545
 drm_atomic_helper_page_flip+0xd2/0x180 drivers/gpu/drm/drm_atomic_helper.c:3696
 drm_mode_page_flip_ioctl+0x1044/0x1470 drivers/gpu/drm/drm_plane.c:1516
 drm_ioctl_kernel+0x1e6/0x3d0 drivers/gpu/drm/drm_ioctl.c:745
 drm_ioctl+0x5d6/0xc00 drivers/gpu/drm/drm_ioctl.c:842
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18f/0x220 fs/ioctl.c:893
page last free pid 6757 tgid 6757 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1112 [inline]
 free_unref_page+0x5f4/0xdc0 mm/page_alloc.c:2642
 __put_partials+0x14c/0x170 mm/slub.c:3145
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:247 [inline]
 slab_post_alloc_hook mm/slub.c:4085 [inline]
 slab_alloc_node mm/slub.c:4134 [inline]
 __kmalloc_cache_noprof+0x11e/0x300 mm/slub.c:4290
 kmalloc_noprof include/linux/slab.h:878 [inline]
 kzalloc_noprof include/linux/slab.h:1014 [inline]
 drm_file_alloc+0x74/0x9a0 drivers/gpu/drm/drm_file.c:137
 drm_open_helper+0x202/0x540 drivers/gpu/drm/drm_file.c:318
 drm_open+0x1a0/0x3e0 drivers/gpu/drm/drm_file.c:371
 drm_stub_open+0x20c/0x380 drivers/gpu/drm/drm_drv.c:1049
 chrdev_open+0x237/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x6ca/0x1530 fs/open.c:958
 vfs_open+0x82/0x3f0 fs/open.c:1088
 do_open fs/namei.c:3774 [inline]
 path_openat+0x1e6a/0x2d60 fs/namei.c:3933
 do_filp_open+0x1dc/0x430 fs/namei.c:3960
 do_sys_openat2+0x17a/0x1e0 fs/open.c:1415

Memory state around the buggy address:
 ffff888035333700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888035333780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888035333800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888035333880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888035333900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/12 18:36 upstream 2d5404caa8c7 c819f227 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-use-after-free Read in drm_atomic_helper_wait_for_vblanks
2024/02/13 14:07 upstream c664e16bb1ba e66542d7 .config console log report syz C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-use-after-free Read in drm_atomic_helper_wait_for_vblanks
2024/02/11 07:59 upstream a5b6244cf87c 77b23aa1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-use-after-free Read in drm_atomic_helper_wait_for_vblanks
2024/09/18 08:27 upstream a430d95c5efa c673ca06 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-use-after-free Read in drm_atomic_helper_wait_for_vblanks
* Struck through repros no longer work on HEAD.