RDX: 0000000020000100 RSI: 0000000000005423 RDI: 0000000000000004 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f831a33c6d4 R13: 00000000004c18ff R14: 00000000004d3b28 R15: 0000000000000005 ================================================================== BUG: KASAN: double-free or invalid-free in x25_asy_free+0x37/0x140 drivers/net/wan/x25_asy.c:111 CPU: 1 PID: 10584 Comm: syz-executor0 Not tainted 4.20.0+ #389 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d3/0x2c6 lib/dump_stack.c:113 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256 kasan_report_invalid_free+0x64/0xa0 mm/kasan/report.c:336 __kasan_slab_free+0x13a/0x150 mm/kasan/kasan.c:501 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3817 x25_asy_free+0x37/0x140 drivers/net/wan/x25_asy.c:111 x25_asy_open_tty+0x6ad/0x7e7 drivers/net/wan/x25_asy.c:572 tty_ldisc_open.isra.1+0x8b/0xe0 drivers/tty/tty_ldisc.c:453 tty_set_ldisc+0x2dc/0x6a0 drivers/tty/tty_ldisc.c:578 tiocsetd drivers/tty/tty_io.c:2321 [inline] tty_ioctl+0x39d/0x17d0 drivers/tty/tty_io.c:2581 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457759 Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f831a33bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f831a33bc90 RCX: 0000000000457759 RDX: 0000000020000100 RSI: 0000000000005423 RDI: 0000000000000004 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f831a33c6d4 R13: 00000000004c18ff R14: 00000000004d3b28 R15: 0000000000000005 input: syz1 as /devices/virtual/input/input69 Allocated by task 10584: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 __do_kmalloc mm/slab.c:3722 [inline] __kmalloc+0x15b/0x770 mm/slab.c:3731 kmalloc include/linux/slab.h:551 [inline] x25_asy_open drivers/net/wan/x25_asy.c:465 [inline] x25_asy_open_tty+0x32a/0x7e7 drivers/net/wan/x25_asy.c:570 tty_ldisc_open.isra.1+0x8b/0xe0 drivers/tty/tty_ldisc.c:453 tty_set_ldisc+0x2dc/0x6a0 drivers/tty/tty_ldisc.c:578 tiocsetd drivers/tty/tty_io.c:2321 [inline] tty_ioctl+0x39d/0x17d0 drivers/tty/tty_io.c:2581 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 10584: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3817 x25_asy_open drivers/net/wan/x25_asy.c:489 [inline] x25_asy_open_tty+0x6a0/0x7e7 drivers/net/wan/x25_asy.c:570 tty_ldisc_open.isra.1+0x8b/0xe0 drivers/tty/tty_ldisc.c:453 tty_set_ldisc+0x2dc/0x6a0 drivers/tty/tty_ldisc.c:578 tiocsetd drivers/tty/tty_io.c:2321 [inline] tty_ioctl+0x39d/0x17d0 drivers/tty/tty_io.c:2581 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8881b4b10940 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes inside of 1024-byte region [ffff8881b4b10940, ffff8881b4b10d40) The buggy address belongs to the page: page:ffffea0006d2c400 count:1 mapcount:0 mapping:ffff8881da800ac0 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000010200(slab|head) raw: 02fffc0000010200 ffffea0006c21308 ffffea000745f688 ffff8881da800ac0 raw: 0000000000000000 ffff8881b4b10040 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881b4b10800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881b4b10880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff8881b4b10900: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8881b4b10980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881b4b10a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================