syzbot

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BUG: KASAN: slab-use-after-free in drm_atomic_helper_wait_for_vblanks.part.0+0x847/0x920 drivers/gpu/drm/drm_atomic_helper.c:1650
Read of size 1 at addr ffff888023d92c09 by task kworker/u16:23/24907

CPU: 2 PID: 24907 Comm: kworker/u16:23 Not tainted 6.6.0-rc5-syzkaller-00067-g8182d7a3f1b8 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: events_unbound commit_work
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:364 [inline]
 print_report+0xc4/0x620 mm/kasan/report.c:475
 kasan_report+0xda/0x110 mm/kasan/report.c:588
 drm_atomic_helper_wait_for_vblanks.part.0+0x847/0x920 drivers/gpu/drm/drm_atomic_helper.c:1650
 drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1646 [inline]
 drm_atomic_helper_commit_tail+0xcb/0xf0 drivers/gpu/drm/drm_atomic_helper.c:1746
 commit_tail+0x32c/0x410 drivers/gpu/drm/drm_atomic_helper.c:1823
 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
 kthread+0x33c/0x440 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>

Allocated by task 14732:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:599 [inline]
 drm_atomic_helper_crtc_duplicate_state+0x6c/0xc0 drivers/gpu/drm/drm_atomic_state_helper.c:177
 drm_simple_kms_crtc_duplicate_state+0x86/0xb0 drivers/gpu/drm/drm_simple_kms_helper.c:166
 drm_atomic_get_crtc_state+0x15b/0x430 drivers/gpu/drm/drm_atomic.c:362
 page_flip_common+0x57/0x310 drivers/gpu/drm/drm_atomic_helper.c:3589
 drm_atomic_helper_page_flip+0xb6/0x190 drivers/gpu/drm/drm_atomic_helper.c:3650
 drm_mode_page_flip_ioctl+0xf83/0x12c0 drivers/gpu/drm/drm_plane.c:1373
 drm_ioctl_kernel+0x280/0x4c0 drivers/gpu/drm/drm_ioctl.c:789
 drm_ioctl+0x5cb/0xbf0 drivers/gpu/drm/drm_ioctl.c:892
 drm_compat_ioctl+0x322/0x460 drivers/gpu/drm/drm_ioc32.c:988
 __do_compat_sys_ioctl+0x2bf/0x330 fs/ioctl.c:972
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

Freed by task 14729:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x15b/0x1b0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1800 [inline]
 slab_free_freelist_hook+0x114/0x1e0 mm/slub.c:1826
 slab_free mm/slub.c:3809 [inline]
 __kmem_cache_free+0xb8/0x2f0 mm/slub.c:3822
 drm_simple_kms_crtc_destroy_state+0x8f/0xb0 drivers/gpu/drm/drm_simple_kms_helper.c:177
 drm_atomic_state_default_clear+0x3a7/0xde0 drivers/gpu/drm/drm_atomic.c:225
 drm_atomic_state_clear drivers/gpu/drm/drm_atomic.c:294 [inline]
 __drm_atomic_state_free+0x17f/0x2b0 drivers/gpu/drm/drm_atomic.c:311
 kref_put include/linux/kref.h:65 [inline]
 drm_atomic_state_put include/drm/drm_atomic.h:490 [inline]
 drm_client_modeset_commit_atomic+0x6d5/0x810 drivers/gpu/drm/drm_client_modeset.c:1057
 drm_client_modeset_commit_locked+0x14d/0x570 drivers/gpu/drm/drm_client_modeset.c:1154
 drm_client_modeset_commit+0x4f/0x80 drivers/gpu/drm/drm_client_modeset.c:1180
 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:251 [inline]
 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:230 [inline]
 drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:278 [inline]
 drm_fb_helper_lastclose+0xc7/0x160 drivers/gpu/drm/drm_fb_helper.c:2005
 drm_fbdev_generic_client_restore+0x2c/0x40 drivers/gpu/drm/drm_fbdev_generic.c:258
 drm_client_dev_restore+0x188/0x290 drivers/gpu/drm/drm_client.c:257
 drm_release+0x40e/0x4f0 drivers/gpu/drm/drm_file.c:497
 __fput+0x3f7/0xa70 fs/file_table.c:384
 __fput_sync+0x47/0x50 fs/file_table.c:465
 __do_sys_close fs/open.c:1572 [inline]
 __se_sys_close fs/open.c:1557 [inline]
 __ia32_sys_close+0x87/0xf0 fs/open.c:1557
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

The buggy address belongs to the object at ffff888023d92c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 9 bytes inside of
 freed 512-byte region [ffff888023d92c00, ffff888023d92e00)

The buggy address belongs to the physical page:
page:ffffea00008f6400 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888023d92800 pfn:0x23d90
head:ffffea00008f6400 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888012c42c80 ffffea0000874200 0000000000000003
raw: ffff888023d92800 000000008010000f 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 14400, tgid 14399 (syz-executor.0), ts 1445849892711, free_ts 1445521863826
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0xee0/0x2f20 mm/page_alloc.c:3170
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4426
 __alloc_pages_node include/linux/gfp.h:237 [inline]
 alloc_slab_page mm/slub.c:1872 [inline]
 allocate_slab+0xa1/0x380 mm/slub.c:2017
 new_slab mm/slub.c:2070 [inline]
 ___slab_alloc+0x8c7/0x1580 mm/slub.c:3223
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3322
 __slab_alloc_node mm/slub.c:3375 [inline]
 slab_alloc_node mm/slub.c:3468 [inline]
 __kmem_cache_alloc_node+0x131/0x340 mm/slub.c:3517
 __do_kmalloc_node mm/slab_common.c:1022 [inline]
 __kmalloc_node+0x52/0x110 mm/slab_common.c:1030
 kmalloc_array_node include/linux/slab.h:697 [inline]
 kcalloc_node include/linux/slab.h:702 [inline]
 memcg_alloc_slab_cgroups+0xa9/0x170 mm/memcontrol.c:2895
 account_slab mm/slab.h:636 [inline]
 allocate_slab+0x2cb/0x380 mm/slub.c:2035
 new_slab mm/slub.c:2070 [inline]
 ___slab_alloc+0x8c7/0x1580 mm/slub.c:3223
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3322
 __slab_alloc_node mm/slub.c:3375 [inline]
 slab_alloc_node mm/slub.c:3468 [inline]
 __kmem_cache_alloc_node+0x131/0x340 mm/slub.c:3517
 kmalloc_trace+0x25/0xe0 mm/slab_common.c:1114
 kmalloc include/linux/slab.h:599 [inline]
 kzalloc include/linux/slab.h:720 [inline]
 kvm_create_vm_debugfs arch/x86/kvm/../../../virt/kvm/kvm_main.c:1099 [inline]
 kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1242 [inline]
 kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:5089 [inline]
 kvm_dev_ioctl+0x1543/0x1c20 arch/x86/kvm/../../../virt/kvm/kvm_main.c:5131
 __do_compat_sys_ioctl+0x2bf/0x330 fs/ioctl.c:972
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2312
 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2405
 __unfreeze_partials+0x21d/0x240 mm/slub.c:2655
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x18e/0x1d0 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x65/0x90 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook mm/slab.h:762 [inline]
 slab_alloc_node mm/slub.c:3478 [inline]
 slab_alloc mm/slub.c:3486 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3493 [inline]
 kmem_cache_alloc+0x16c/0x3b0 mm/slub.c:3502
 getname_flags.part.0+0x50/0x4d0 fs/namei.c:140
 getname_flags+0x9c/0xf0 include/linux/audit.h:321
 user_path_at_empty+0x2c/0x60 fs/namei.c:2909
 user_path_at include/linux/namei.h:57 [inline]
 __do_sys_chdir fs/open.c:551 [inline]
 __se_sys_chdir fs/open.c:545 [inline]
 __ia32_sys_chdir+0xce/0x270 fs/open.c:545
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

Memory state around the buggy address:
 ffff888023d92b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888023d92b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888023d92c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888023d92c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888023d92d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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