================================================================== BUG: KASAN: use-after-free in get_disk_and_module block/genhd.c:1787 [inline] BUG: KASAN: use-after-free in exact_lock+0x38/0xc0 block/genhd.c:677 Read of size 8 at addr ffff888109536460 by task syz.1.3779/14584 CPU: 0 PID: 14584 Comm: syz.1.3779 Tainted: G W 5.10.237-syzkaller-00309-g7e2543346ff7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0xe2/0x130 mm/kasan/report.c:452 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309 get_disk_and_module block/genhd.c:1787 [inline] exact_lock+0x38/0xc0 block/genhd.c:677 kobj_lookup+0x298/0x430 drivers/base/map.c:119 get_gendisk+0xe9/0x340 block/genhd.c:1001 bdev_get_gendisk fs/block_dev.c:1110 [inline] __blkdev_get+0x1b0/0x12f0 fs/block_dev.c:1474 blkdev_get fs/block_dev.c:1653 [inline] blkdev_open+0x208/0x430 fs/block_dev.c:1770 do_dentry_open+0x793/0x1090 fs/open.c:819 vfs_open+0x73/0x80 fs/open.c:942 do_open fs/namei.c:3391 [inline] path_openat+0x27ad/0x3160 fs/namei.c:3509 do_filp_open+0x1b3/0x3e0 fs/namei.c:3536 do_sys_openat2+0x14c/0x6d0 fs/open.c:1217 do_sys_open fs/open.c:1233 [inline] __do_sys_openat fs/open.c:1249 [inline] __se_sys_openat fs/open.c:1244 [inline] __x64_sys_openat+0x136/0x160 fs/open.c:1244 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f643f0da969 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:00007f643d743038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f643f301fa0 RCX: 00007f643f0da969 RDX: 0000000000048080 RSI: 0000200000000040 RDI: ffffffffffffff9c RBP: 00007f643f15cab1 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000006d R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f643f301fa0 R15: 00007fff47c1d5c8 Allocated by task 14464: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] ____kasan_kmalloc mm/kasan/common.c:509 [inline] __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] kmem_cache_alloc_trace+0x184/0x2e0 mm/slub.c:2974 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] copy_verifier_state+0x5a2/0xc20 kernel/bpf/verifier.c:913 push_stack+0x19b/0x4f0 kernel/bpf/verifier.c:989 check_cond_jmp_op kernel/bpf/verifier.c:8286 [inline] do_check+0xb7df/0xdf40 kernel/bpf/verifier.c:10313 do_check_common+0x8e3/0x1160 kernel/bpf/verifier.c:12047 do_check_main kernel/bpf/verifier.c:12110 [inline] bpf_check+0x9371/0xd720 kernel/bpf/verifier.c:12665 bpf_prog_load+0xf5a/0x1420 kernel/bpf/syscall.c:2234 __do_sys_bpf kernel/bpf/syscall.c:4435 [inline] __se_sys_bpf+0x442/0x680 kernel/bpf/syscall.c:4391 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:4391 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 14464: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:220 [inline] slab_free_hook mm/slub.c:1595 [inline] slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1621 slab_free mm/slub.c:3203 [inline] kfree+0xc0/0x270 mm/slub.c:4191 free_func_state kernel/bpf/verifier.c:839 [inline] free_verifier_state+0xde/0x220 kernel/bpf/verifier.c:855 pop_stack+0x39c/0x520 kernel/bpf/verifier.c:964 do_check+0x8783/0xdf40 kernel/bpf/verifier.c:10302 do_check_common+0x8e3/0x1160 kernel/bpf/verifier.c:12047 do_check_main kernel/bpf/verifier.c:12110 [inline] bpf_check+0x9371/0xd720 kernel/bpf/verifier.c:12665 bpf_prog_load+0xf5a/0x1420 kernel/bpf/syscall.c:2234 __do_sys_bpf kernel/bpf/syscall.c:4435 [inline] __se_sys_bpf+0x442/0x680 kernel/bpf/syscall.c:4391 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:4391 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2976 [inline] call_rcu+0x105/0x1040 kernel/rcu/tree.c:3050 netlink_release+0x1288/0x1690 net/netlink/af_netlink.c:796 __sock_release net/socket.c:597 [inline] sock_close+0xe0/0x270 net/socket.c:1286 __fput+0x2fb/0x770 fs/file_table.c:281 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x127/0x190 kernel/task_work.c:189 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop+0xcb/0xe0 kernel/entry/common.c:172 exit_to_user_mode_prepare kernel/entry/common.c:199 [inline] syscall_exit_to_user_mode+0x68/0x90 kernel/entry/common.c:274 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff888109536000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1120 bytes inside of 2048-byte region [ffff888109536000, ffff888109536800) The buggy address belongs to the page: page:ffffea0004254c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109530 head:ffffea0004254c00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 0000000000000000 0000000100000001 ffff888100042d80 raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 2115110238, free_ts 0 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x179/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5349 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1808 [inline] new_slab+0x84/0x3f0 mm/slub.c:1869 new_slab_objects mm/slub.c:2627 [inline] ___slab_alloc+0x2a6/0x450 mm/slub.c:2791 __slab_alloc+0x63/0xa0 mm/slub.c:2831 slab_alloc_node mm/slub.c:2913 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc_trace+0x1b3/0x2e0 mm/slub.c:2972 kmem_cache_alloc_node_trace include/linux/slab.h:440 [inline] kmalloc_node include/linux/slab.h:570 [inline] kzalloc_node include/linux/slab.h:675 [inline] bdi_alloc+0x4e/0x110 mm/backing-dev.c:746 blk_alloc_queue+0x103/0x610 block/blk-core.c:535 brd_alloc+0xfe/0x3e0 drivers/block/brd.c:383 brd_init+0x125/0x468 drivers/block/brd.c:517 do_one_initcall+0x187/0x510 init/main.c:1197 do_initcall_level+0x16f/0x2cf init/main.c:1270 do_initcalls+0x50/0x92 init/main.c:1286 do_basic_setup+0x88/0x8f init/main.c:1306 kernel_init_freeable+0x287/0x3be init/main.c:1510 page_owner free stack trace missing Memory state around the buggy address: ffff888109536300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888109536380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888109536400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888109536480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888109536500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067] CPU: 1 PID: 14584 Comm: syz.1.3779 Tainted: G B W 5.10.237-syzkaller-00309-g7e2543346ff7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:get_disk_and_module block/genhd.c:1789 [inline] RIP: 0010:exact_lock+0x4b/0xc0 block/genhd.c:677 Code: 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 38 f8 6d ff 4d 8b 36 4d 85 f6 74 35 49 83 c6 68 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 16 f8 6d ff 4d 8b 36 4d 85 f6 74 RSP: 0018:ffffc90000b97630 EFLAGS: 00010207 RAX: 000000000000000c RBX: ffff888109536000 RCX: 0000000000000282 RDX: 0000000000000000 RSI: 000000000000000f RDI: 00000000ffffffff RBP: ffffc90000b97648 R08: 0000000000000004 R09: 0000000000000003 R10: fffffbfff0d8e248 R11: 1ffffffff0d8e248 R12: ffff888109536000 R13: 0000000000700002 R14: 0000000000000067 R15: dffffc0000000000 FS: 00007f643d7436c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffd88f0000 CR3: 000000011c769000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kobj_lookup+0x298/0x430 drivers/base/map.c:119 get_gendisk+0xe9/0x340 block/genhd.c:1001 bdev_get_gendisk fs/block_dev.c:1110 [inline] __blkdev_get+0x1b0/0x12f0 fs/block_dev.c:1474 blkdev_get fs/block_dev.c:1653 [inline] blkdev_open+0x208/0x430 fs/block_dev.c:1770 do_dentry_open+0x793/0x1090 fs/open.c:819 vfs_open+0x73/0x80 fs/open.c:942 do_open fs/namei.c:3391 [inline] path_openat+0x27ad/0x3160 fs/namei.c:3509 do_filp_open+0x1b3/0x3e0 fs/namei.c:3536 do_sys_openat2+0x14c/0x6d0 fs/open.c:1217 do_sys_open fs/open.c:1233 [inline] __do_sys_openat fs/open.c:1249 [inline] __se_sys_openat fs/open.c:1244 [inline] __x64_sys_openat+0x136/0x160 fs/open.c:1244 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f643f0da969 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:00007f643d743038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f643f301fa0 RCX: 00007f643f0da969 RDX: 0000000000048080 RSI: 0000200000000040 RDI: ffffffffffffff9c RBP: 00007f643f15cab1 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000006d R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f643f301fa0 R15: 00007fff47c1d5c8 Modules linked in: ---[ end trace 4c1cf78c74377dda ]--- RIP: 0010:get_disk_and_module block/genhd.c:1789 [inline] RIP: 0010:exact_lock+0x4b/0xc0 block/genhd.c:677 Code: 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 38 f8 6d ff 4d 8b 36 4d 85 f6 74 35 49 83 c6 68 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 16 f8 6d ff 4d 8b 36 4d 85 f6 74 RSP: 0018:ffffc90000b97630 EFLAGS: 00010207 RAX: 000000000000000c RBX: ffff888109536000 RCX: 0000000000000282 RDX: 0000000000000000 RSI: 000000000000000f RDI: 00000000ffffffff RBP: ffffc90000b97648 R08: 0000000000000004 R09: 0000000000000003 R10: fffffbfff0d8e248 R11: 1ffffffff0d8e248 R12: ffff888109536000 R13: 0000000000700002 R14: 0000000000000067 R15: dffffc0000000000 FS: 00007f643d7436c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffd88f0000 CR3: 000000011c769000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 00 4c 89 f0 add %cl,-0x10(%rcx,%rcx,4) 4: 48 c1 e8 03 shr $0x3,%rax 8: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) d: 74 08 je 0x17 f: 4c 89 f7 mov %r14,%rdi 12: e8 38 f8 6d ff call 0xff6df84f 17: 4d 8b 36 mov (%r14),%r14 1a: 4d 85 f6 test %r14,%r14 1d: 74 35 je 0x54 1f: 49 83 c6 68 add $0x68,%r14 23: 4c 89 f0 mov %r14,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 4c 89 f7 mov %r14,%rdi 34: e8 16 f8 6d ff call 0xff6df84f 39: 4d 8b 36 mov (%r14),%r14 3c: 4d 85 f6 test %r14,%r14 3f: 74 .byte 0x74