================================================================== BUG: KASAN: use-after-free in post_one_notification.isra.0+0x727/0x990 kernel/watch_queue.c:133 Read of size 4 at addr ffff88807c9e1a70 by task syz-executor.1/4126 CPU: 0 PID: 4126 Comm: syz-executor.1 Not tainted 5.18.0-rc5-syzkaller-00006-g9050ba3a61a4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0xeb/0x467 mm/kasan/report.c:313 print_report mm/kasan/report.c:429 [inline] kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491 post_one_notification.isra.0+0x727/0x990 kernel/watch_queue.c:133 remove_watch_from_object+0x35a/0x9d0 kernel/watch_queue.c:527 keyctl_watch_key+0x346/0x510 security/keys/keyctl.c:1827 __do_sys_keyctl+0x41c/0x500 security/keys/keyctl.c:2016 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: 0033:0x7fb109c890e9 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb108bdd168 EFLAGS: 00000246 ORIG_RAX: 00000000000000fa RAX: ffffffffffffffda RBX: 00007fb109d9c030 RCX: 00007fb109c890e9 RDX: 0000000000000003 RSI: 00000000340d94d0 RDI: 0000000000000020 RBP: 00007fb109ce308d R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc4908e5af R14: 00007fb108bdd300 R15: 0000000000022000 Allocated by task 4123: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline] __kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524 kasan_kmalloc include/linux/kasan.h:234 [inline] __do_kmalloc mm/slab.c:3710 [inline] __kmalloc+0x209/0x4d0 mm/slab.c:3719 kcalloc include/linux/slab.h:652 [inline] alloc_pipe_info+0x1e9/0x590 fs/pipe.c:807 get_pipe_inode fs/pipe.c:881 [inline] create_pipe_files+0x8d/0x880 fs/pipe.c:913 __do_pipe_flags fs/pipe.c:962 [inline] do_pipe2+0x96/0x1b0 fs/pipe.c:1010 __do_sys_pipe2 fs/pipe.c:1028 [inline] __se_sys_pipe2 fs/pipe.c:1026 [inline] __x64_sys_pipe2+0x50/0x70 fs/pipe.c:1026 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 4123: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0x13d/0x180 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:200 [inline] __cache_free mm/slab.c:3439 [inline] kfree+0x113/0x310 mm/slab.c:3810 pipe_resize_ring+0x1df/0x4c0 fs/pipe.c:1295 watch_queue_set_size+0x1d0/0x640 kernel/watch_queue.c:247 pipe_ioctl+0xac/0x2b0 fs/pipe.c:632 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 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 The buggy address belongs to the object at ffff88807c9e1800 which belongs to the cache kmalloc-cg-1k of size 1024 The buggy address is located 624 bytes inside of 1024-byte region [ffff88807c9e1800, ffff88807c9e1c00) The buggy address belongs to the physical page: page:ffffea0001f27840 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7c9e1 memcg:ffff888072aae101 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0001ee8b08 ffffea0001e3d9c8 ffff888010c43b00 raw: 0000000000000000 ffff88807c9e1000 0000000100000002 ffff888072aae101 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x3420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_HARDWALL|__GFP_THISNODE), pid 4123, tgid 4119 (syz-executor.1), ts 129203720063, free_ts 129203299284 prep_new_page mm/page_alloc.c:2441 [inline] get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4182 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5408 __alloc_pages_node include/linux/gfp.h:587 [inline] kmem_getpages mm/slab.c:1378 [inline] cache_grow_begin+0x75/0x350 mm/slab.c:2584 cache_alloc_refill+0x27f/0x380 mm/slab.c:2957 ____cache_alloc mm/slab.c:3040 [inline] ____cache_alloc mm/slab.c:3023 [inline] __do_cache_alloc mm/slab.c:3267 [inline] slab_alloc mm/slab.c:3309 [inline] __do_kmalloc mm/slab.c:3708 [inline] __kmalloc+0x3b3/0x4d0 mm/slab.c:3719 kcalloc include/linux/slab.h:652 [inline] alloc_pipe_info+0x1e9/0x590 fs/pipe.c:807 get_pipe_inode fs/pipe.c:881 [inline] create_pipe_files+0x8d/0x880 fs/pipe.c:913 __do_pipe_flags fs/pipe.c:962 [inline] do_pipe2+0x96/0x1b0 fs/pipe.c:1010 __do_sys_pipe2 fs/pipe.c:1028 [inline] __se_sys_pipe2 fs/pipe.c:1026 [inline] __x64_sys_pipe2+0x50/0x70 fs/pipe.c:1026 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 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1356 [inline] free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1406 free_unref_page_prepare mm/page_alloc.c:3328 [inline] free_unref_page+0x19/0x6a0 mm/page_alloc.c:3423 __vunmap+0x85d/0xd30 mm/vmalloc.c:2667 free_work+0x58/0x70 mm/vmalloc.c:97 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Memory state around the buggy address: ffff88807c9e1900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807c9e1980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807c9e1a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807c9e1a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807c9e1b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================