netlink: 16 bytes leftover after parsing attributes in process `syz-executor.0'. ================================================================== BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x22c/0x240 drivers/gpu/drm/vgem/vgem_drv.c:214 Read of size 8 at addr ffff8880b4fd1440 by task syz-executor.2/20405 CPU: 0 PID: 20405 Comm: syz-executor.2 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354 kasan_report mm/kasan/report.c:412 [inline] __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433 vgem_gem_dumb_create+0x22c/0x240 drivers/gpu/drm/vgem/vgem_drv.c:214 batman_adv: Cannot find parent device drm_mode_create_dumb+0x27c/0x300 drivers/gpu/drm/drm_dumb_buffers.c:92 drm_ioctl_kernel+0x208/0x2a0 drivers/gpu/drm/drm_ioctl.c:758 device gretap1 entered promiscuous mode drm_ioctl+0x5a0/0x9e0 drivers/gpu/drm/drm_ioctl.c:861 x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f8aa35cf0f9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8aa1b41168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING RAX: ffffffffffffffda RBX: 00007f8aa36eef80 RCX: 00007f8aa35cf0f9 RDX: 0000000020000040 RSI: 00000000c02064b2 RDI: 0000000000000005 RBP: 00007f8aa362aae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffca18141f R14: 00007f8aa1b41300 R15: 0000000000022000 Allocated by task 20405: kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] __vgem_gem_create+0x44/0xf0 drivers/gpu/drm/vgem/vgem_drv.c:158 vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:187 [inline] vgem_gem_dumb_create+0xcf/0x240 drivers/gpu/drm/vgem/vgem_drv.c:210 drm_mode_create_dumb+0x27c/0x300 drivers/gpu/drm/drm_dumb_buffers.c:92 drm_ioctl_kernel+0x208/0x2a0 drivers/gpu/drm/drm_ioctl.c:758 drm_ioctl+0x5a0/0x9e0 drivers/gpu/drm/drm_ioctl.c:861 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688 x_tables: ip6_tables: realm match: used from hooks PREROUTING, but only valid from INPUT/FORWARD/OUTPUT/POSTROUTING ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 20405: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 drm_gem_object_free+0x91/0x1c0 drivers/gpu/drm/drm_gem.c:837 kref_put include/linux/kref.h:70 [inline] drm_gem_object_put_unlocked+0xd1/0x180 drivers/gpu/drm/drm_gem.c:866 vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:192 [inline] vgem_gem_dumb_create+0x10c/0x240 drivers/gpu/drm/vgem/vgem_drv.c:210 drm_mode_create_dumb+0x27c/0x300 drivers/gpu/drm/drm_dumb_buffers.c:92 drm_ioctl_kernel+0x208/0x2a0 drivers/gpu/drm/drm_ioctl.c:758 drm_ioctl+0x5a0/0x9e0 drivers/gpu/drm/drm_ioctl.c:861 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880b4fd1340 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 256 bytes inside of 512-byte region [ffff8880b4fd1340, ffff8880b4fd1540) The buggy address belongs to the page: page:ffffea0002d3f440 count:1 mapcount:0 mapping:ffff88813bff0940 index:0xffff8880b4fd1ac0 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffffea0002691988 ffffea000297f408 ffff88813bff0940 raw: ffff8880b4fd1ac0 ffff8880b4fd10c0 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880b4fd1300: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8880b4fd1380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880b4fd1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880b4fd1480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880b4fd1500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ================================================================== netlink: 12 bytes leftover after parsing attributes in process `syz-executor.0'. netlink: 16 bytes leftover after parsing attributes in process `syz-executor.0'.