================================================================== BUG: KASAN: use-after-free in fb_mode_is_equal+0x284/0x2f0 drivers/video/fbdev/core/modedb.c:924 Read of size 4 at addr ffff8880371b351c by task syz-executor.0/29320 CPU: 1 PID: 29320 Comm: syz-executor.0 Tainted: G W 5.13.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:96 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233 __kasan_report mm/kasan/report.c:419 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:436 fb_mode_is_equal+0x284/0x2f0 drivers/video/fbdev/core/modedb.c:924 fbcon_mode_deleted+0x13d/0x1d0 drivers/video/fbdev/core/fbcon.c:2718 fb_set_var+0xae1/0xda0 drivers/video/fbdev/core/fbmem.c:975 do_fb_ioctl+0x2f9/0x690 drivers/video/fbdev/core/fbmem.c:1108 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl fs/ioctl.c:1055 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055 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+0x44/0xae RIP: 0033:0x4665d9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007faa5c70f188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9 RDX: 0000000020000040 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 0000000000a9fb1f R14: 00007faa5c70f300 R15: 0000000000022000 Allocated by task 11438: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] ____kasan_kmalloc mm/kasan/common.c:472 [inline] __kasan_kmalloc+0x9b/0xd0 mm/kasan/common.c:522 kmalloc include/linux/slab.h:591 [inline] fb_add_videomode drivers/video/fbdev/core/modedb.c:1073 [inline] fb_add_videomode+0x2fb/0x610 drivers/video/fbdev/core/modedb.c:1057 fb_set_var+0x631/0xda0 drivers/video/fbdev/core/fbmem.c:1049 do_fb_ioctl+0x2f9/0x690 drivers/video/fbdev/core/fbmem.c:1108 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl fs/ioctl.c:1055 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055 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+0x44/0xae Freed by task 29321: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:229 [inline] slab_free_hook mm/slub.c:1639 [inline] slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1664 slab_free mm/slub.c:3224 [inline] kfree+0xeb/0x670 mm/slub.c:4268 fb_delete_videomode+0x3d2/0x570 drivers/video/fbdev/core/modedb.c:1104 fb_set_var+0xaf1/0xda0 drivers/video/fbdev/core/fbmem.c:978 do_fb_ioctl+0x2f9/0x690 drivers/video/fbdev/core/fbmem.c:1108 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl fs/ioctl.c:1055 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055 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+0x44/0xae Last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348 kvfree_call_rcu+0x74/0x8c0 kernel/rcu/tree.c:3597 cfg80211_update_known_bss+0x833/0xa60 net/wireless/scan.c:1661 cfg80211_bss_update+0xef/0x1e00 net/wireless/scan.c:1708 cfg80211_inform_single_bss_frame_data+0x6e8/0xee0 net/wireless/scan.c:2414 cfg80211_inform_bss_frame_data+0xa7/0xb10 net/wireless/scan.c:2447 ieee80211_bss_info_update+0x3ce/0xb60 net/mac80211/scan.c:190 ieee80211_rx_bss_info net/mac80211/ibss.c:1126 [inline] ieee80211_rx_mgmt_probe_beacon+0xcfe/0x17b0 net/mac80211/ibss.c:1615 ieee80211_ibss_rx_queued_mgmt+0xd82/0x15f0 net/mac80211/ibss.c:1642 ieee80211_iface_process_skb net/mac80211/iface.c:1426 [inline] ieee80211_iface_work+0x7f7/0xa40 net/mac80211/iface.c:1462 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Second to last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348 kvfree_call_rcu+0x74/0x8c0 kernel/rcu/tree.c:3597 cfg80211_update_known_bss+0x833/0xa60 net/wireless/scan.c:1661 cfg80211_bss_update+0xef/0x1e00 net/wireless/scan.c:1708 cfg80211_inform_single_bss_frame_data+0x6e8/0xee0 net/wireless/scan.c:2414 cfg80211_inform_bss_frame_data+0xa7/0xb10 net/wireless/scan.c:2447 ieee80211_bss_info_update+0x3ce/0xb60 net/mac80211/scan.c:190 ieee80211_rx_bss_info net/mac80211/ibss.c:1126 [inline] ieee80211_rx_mgmt_probe_beacon+0xcfe/0x17b0 net/mac80211/ibss.c:1615 ieee80211_ibss_rx_queued_mgmt+0xd82/0x15f0 net/mac80211/ibss.c:1642 ieee80211_iface_process_skb net/mac80211/iface.c:1426 [inline] ieee80211_iface_work+0x7f7/0xa40 net/mac80211/iface.c:1462 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 The buggy address belongs to the object at ffff8880371b3500 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 28 bytes inside of 96-byte region [ffff8880371b3500, ffff8880371b3560) The buggy address belongs to the page: page:ffffea0000dc6cc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880371b3100 pfn:0x371b3 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0000dec188 ffffea0000db8288 ffff888011041780 raw: ffff8880371b3100 000000000020000b 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 0x12a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY), pid 20, ts 196252442174, free_ts 196229728205 prep_new_page mm/page_alloc.c:2445 [inline] get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4178 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5386 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2272 alloc_slab_page mm/slub.c:1702 [inline] allocate_slab+0x32b/0x4c0 mm/slub.c:1842 new_slab mm/slub.c:1905 [inline] new_slab_objects mm/slub.c:2651 [inline] ___slab_alloc+0x4ba/0x820 mm/slub.c:2814 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2854 slab_alloc_node mm/slub.c:2936 [inline] slab_alloc mm/slub.c:2978 [inline] kmem_cache_alloc_trace+0x325/0x3c0 mm/slub.c:2995 kmalloc include/linux/slab.h:591 [inline] dst_cow_metrics_generic+0x48/0x1e0 net/core/dst.c:201 dst_metrics_write_ptr include/net/dst.h:118 [inline] dst_metric_set include/net/dst.h:179 [inline] icmp6_dst_alloc+0x4f5/0x6c0 net/ipv6/route.c:3291 ndisc_send_skb+0x1232/0x1750 net/ipv6/ndisc.c:488 ndisc_send_ns+0x3a9/0x840 net/ipv6/ndisc.c:650 addrconf_dad_work+0xc3f/0x1340 net/ipv6/addrconf.c:4119 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1355 [inline] free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1406 free_unref_page_prepare mm/page_alloc.c:3341 [inline] free_unref_page_list+0x1a1/0x1050 mm/page_alloc.c:3457 release_pages+0x856/0x20a0 mm/swap.c:972 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:242 [inline] tlb_flush_mmu mm/mmu_gather.c:249 [inline] tlb_finish_mmu+0x165/0x8c0 mm/mmu_gather.c:340 exit_mmap+0x1ea/0x620 mm/mmap.c:3204 __mmput+0x122/0x470 kernel/fork.c:1101 mmput+0x58/0x60 kernel/fork.c:1122 free_bprm+0x65/0x2e0 fs/exec.c:1482 kernel_execve+0x380/0x460 fs/exec.c:1979 call_usermodehelper_exec_async+0x2e3/0x580 kernel/umh.c:112 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Memory state around the buggy address: ffff8880371b3400: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880371b3480: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff8880371b3500: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff8880371b3580: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880371b3600: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ==================================================================