================================================================== BUG: KASAN: double-free or invalid-free in relay_open+0x6a1/0xa40 kernel/relay.c:614 CPU: 0 PID: 12593 Comm: syz-executor6 Not tainted 4.15.0+ #285 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_double_free+0x55/0x80 mm/kasan/report.c:333 kasan_slab_free+0xa3/0xc0 mm/kasan/kasan.c:514 __cache_free mm/slab.c:3488 [inline] kfree+0xd6/0x260 mm/slab.c:3803 relay_open+0x6a1/0xa40 kernel/relay.c:614 do_blk_trace_setup+0x4a4/0xcd0 kernel/trace/blktrace.c:544 __blk_trace_setup+0xbe/0x150 kernel/trace/blktrace.c:589 blk_trace_ioctl+0x206/0x2e0 kernel/trace/blktrace.c:728 blkdev_ioctl+0x1845/0x1e00 block/ioctl.c:587 block_ioctl+0xde/0x120 fs/block_dev.c:1860 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007fa6f8590c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000453299 RDX: 0000000020dc6000 RSI: 00000000c0481273 RDI: 0000000000000014 RBP: 000000000000061d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f8358 R13: 00000000ffffffff R14: 00007fa6f85916d4 R15: 0000000000000000 Allocated by task 12593: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3610 kmalloc include/linux/slab.h:499 [inline] kzalloc include/linux/slab.h:688 [inline] relay_open+0xf2/0xa40 kernel/relay.c:576 do_blk_trace_setup+0x4a4/0xcd0 kernel/trace/blktrace.c:544 __blk_trace_setup+0xbe/0x150 kernel/trace/blktrace.c:589 blk_trace_ioctl+0x206/0x2e0 kernel/trace/blktrace.c:728 blkdev_ioctl+0x1845/0x1e00 block/ioctl.c:587 block_ioctl+0xde/0x120 fs/block_dev.c:1860 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x29/0xa0 Freed by task 12593: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3488 [inline] kfree+0xd6/0x260 mm/slab.c:3803 relay_destroy_channel kernel/relay.c:199 [inline] kref_put include/linux/kref.h:70 [inline] relay_open+0x84a/0xa40 kernel/relay.c:612 do_blk_trace_setup+0x4a4/0xcd0 kernel/trace/blktrace.c:544 __blk_trace_setup+0xbe/0x150 kernel/trace/blktrace.c:589 blk_trace_ioctl+0x206/0x2e0 kernel/trace/blktrace.c:728 blkdev_ioctl+0x1845/0x1e00 block/ioctl.c:587 block_ioctl+0xde/0x120 fs/block_dev.c:1860 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x29/0xa0 The buggy address belongs to the object at ffff8801b6e070c0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 0 bytes inside of 512-byte region [ffff8801b6e070c0, ffff8801b6e072c0) The buggy address belongs to the page: page:ffffea0006db81c0 count:1 mapcount:0 mapping:ffff8801b6e070c0 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801b6e070c0 0000000000000000 0000000100000006 raw: ffffea00072ce960 ffffea0006bd83a0 ffff8801db000940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b6e06f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801b6e07000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801b6e07080: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8801b6e07100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b6e07180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================