================================================================== BUG: KASAN: slab-use-after-free in nr_dec_obs net/netrom/nr_route.c:471 [inline] BUG: KASAN: slab-use-after-free in nr_rt_ioctl+0x595/0xfb0 net/netrom/nr_route.c:692 Read of size 2 at addr ffff88802a25c332 by task syz.2.1523/10068 CPU: 0 UID: 0 PID: 10068 Comm: syz.2.1523 Not tainted 6.13.0-rc6-syzkaller-00262-gb62cef9a5c67 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x23d/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x165/0x540 mm/kasan/report.c:489 kasan_report+0x13f/0x180 mm/kasan/report.c:602 nr_dec_obs net/netrom/nr_route.c:471 [inline] nr_rt_ioctl+0x595/0xfb0 net/netrom/nr_route.c:692 sock_do_ioctl+0x154/0x460 net/socket.c:1209 sock_ioctl+0x622/0x8e0 net/socket.c:1328 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x7e/0x180 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f7349d85d29 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f734ac78038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f7349f75fa0 RCX: 00007f7349d85d29 RDX: 0000000000000000 RSI: 00000000000089e2 RDI: 0000000000000005 RBP: 00007f7349e01b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f7349f75fa0 R15: 00007ffc45512bf8 Allocated by task 10068: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3b/0x70 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x94/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x237/0x370 mm/slub.c:4329 kmalloc_noprof include/linux/slab.h:901 [inline] nr_add_node+0x852/0x2220 net/netrom/nr_route.c:146 nr_rt_ioctl+0xd3f/0xfb0 net/netrom/nr_route.c:651 sock_do_ioctl+0x154/0x460 net/socket.c:1209 sock_ioctl+0x622/0x8e0 net/socket.c:1328 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x7e/0x180 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e Freed by task 10068: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3b/0x70 mm/kasan/common.c:68 kasan_save_free_info+0x3c/0x50 mm/kasan/generic.c:582 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x55/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4613 [inline] kfree+0x18e/0x410 mm/slub.c:4761 nr_dec_obs net/netrom/nr_route.c:469 [inline] nr_rt_ioctl+0x2e1/0xfb0 net/netrom/nr_route.c:692 sock_do_ioctl+0x154/0x460 net/socket.c:1209 sock_ioctl+0x622/0x8e0 net/socket.c:1328 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x7e/0x180 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e The buggy address belongs to the object at ffff88802a25c300 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 50 bytes inside of freed 64-byte region [ffff88802a25c300, ffff88802a25c340) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a25c anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801a0418c0 ffffea00006fab00 dead000000000005 raw: 0000000000000000 0000000080200020 00000001f5000000 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid 1 (swapper/0), ts 18131325791, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1df/0x220 mm/page_alloc.c:1558 prep_new_page mm/page_alloc.c:1566 [inline] get_page_from_freelist+0x35e2/0x3720 mm/page_alloc.c:3476 __alloc_pages_noprof+0x252/0x680 mm/page_alloc.c:4753 alloc_pages_mpol_noprof+0x3e4/0x670 mm/mempolicy.c:2269 alloc_slab_page+0x6a/0x110 mm/slub.c:2423 allocate_slab+0x5a/0x2a0 mm/slub.c:2589 new_slab mm/slub.c:2642 [inline] ___slab_alloc+0xc35/0x1490 mm/slub.c:3830 __slab_alloc+0x58/0xa0 mm/slub.c:3920 __slab_alloc_node mm/slub.c:3995 [inline] slab_alloc_node mm/slub.c:4156 [inline] __do_kmalloc_node mm/slub.c:4297 [inline] __kmalloc_noprof+0x2da/0x4a0 mm/slub.c:4310 kmalloc_noprof include/linux/slab.h:905 [inline] kmalloc_array_noprof include/linux/slab.h:946 [inline] kobj_map+0x67/0x550 drivers/base/map.c:44 cdev_add+0x91/0x170 fs/char_dev.c:491 __video_register_device+0x3a70/0x4a00 drivers/media/v4l2-core/v4l2-dev.c:1045 video_register_device include/media/v4l2-dev.h:384 [inline] vivid_create_devnodes+0xa67/0x2c90 drivers/media/test-drivers/vivid/vivid-core.c:1469 vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:2040 [inline] vivid_probe+0x5854/0x7ce0 drivers/media/test-drivers/vivid/vivid-core.c:2093 platform_probe+0x136/0x1c0 drivers/base/platform.c:1404 really_probe+0x2b8/0xac0 drivers/base/dd.c:658 page_owner free stack trace missing Memory state around the buggy address: ffff88802a25c200: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ffff88802a25c280: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc >ffff88802a25c300: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88802a25c380: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ffff88802a25c400: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc ==================================================================