ubi0: detaching mtd0 ================================================================== BUG: KASAN: use-after-free in uif_close+0x15e/0x190 drivers/mtd/ubi/build.c:502 Read of size 4 at addr ffff8880567549e8 by task syz-executor.4/15599 CPU: 0 PID: 15599 Comm: syz-executor.4 Not tainted 5.7.0-rc6-next-20200522-syzkaller #0 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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 uif_close+0x15e/0x190 drivers/mtd/ubi/build.c:502 ubi_detach_mtd_dev+0x226/0x432 drivers/mtd/ubi/build.c:1110 ctrl_cdev_ioctl+0x1bf/0x2b0 drivers/mtd/ubi/cdev.c:1068 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45ca29 Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f4bc53fec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e1080 RCX: 000000000045ca29 RDX: 000000000076006e RSI: 0000000040046f41 RDI: 0000000000000003 RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000209 R14: 00000000004c44c1 R15: 00007f4bc53ff6d4 Allocated by task 15592: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc mm/kasan/common.c:494 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] ubi_attach_mtd_dev+0x2e7/0x27c0 drivers/mtd/ubi/build.c:901 ctrl_cdev_ioctl+0x229/0x2b0 drivers/mtd/ubi/cdev.c:1043 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Freed by task 15599: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] kasan_set_free_info mm/kasan/common.c:316 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:455 __cache_free mm/slab.c:3426 [inline] kfree+0x109/0x2b0 mm/slab.c:3757 device_release+0x71/0x200 drivers/base/core.c:1541 kobject_cleanup lib/kobject.c:701 [inline] kobject_release lib/kobject.c:732 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1c8/0x2f0 lib/kobject.c:749 cdev_device_del+0x69/0x80 fs/char_dev.c:575 uif_close+0xea/0x190 drivers/mtd/ubi/build.c:501 ubi_detach_mtd_dev+0x226/0x432 drivers/mtd/ubi/build.c:1110 ctrl_cdev_ioctl+0x1bf/0x2b0 drivers/mtd/ubi/cdev.c:1068 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 The buggy address belongs to the object at ffff888056754000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 2536 bytes inside of 8192-byte region [ffff888056754000, ffff888056756000) The buggy address belongs to the page: page:ffffea000159d500 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea000159d500 order:2 compound_mapcount:0 compound_pincount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea00015f1908 ffff8880aa001b50 ffff8880aa0021c0 raw: 0000000000000000 ffff888056754000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888056754880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888056754900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888056754980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888056754a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888056754a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================