bisecting fixing commit since cbfa1702aaf69b2311ea1b35e04f113c48368c67 building syzkaller on 4a77ae0bdc5cd75ebe88ce7c896aae6bbf457a29 testing commit cbfa1702aaf69b2311ea1b35e04f113c48368c67 with gcc (GCC) 8.1.0 kernel signature: 7bdf91ee2647a046e551ed619d5ef12e962202814550711dc617b5f7a20f56aa all runs: crashed: KASAN: slab-out-of-bounds Read in squashfs_export_iget testing current HEAD e98f3c4269fda898b913259a7d9b60fb38269869 testing commit e98f3c4269fda898b913259a7d9b60fb38269869 with gcc (GCC) 8.1.0 kernel signature: b7e457bf2edb924bc16eea83c1a13301a99604358a1b717ed0eb9037a1efa34c all runs: crashed: KASAN: slab-out-of-bounds Read in squashfs_export_iget revisions tested: 2, total time: 22m46.595099003s (build: 16m41.632991113s, test: 5m27.82323316s) the crash still happens on HEAD commit msg: Linux 4.14.205 crash: KASAN: slab-out-of-bounds Read in squashfs_export_iget batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 ================================================================== batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! BUG: KASAN: slab-out-of-bounds in squashfs_export_iget+0x1aa/0x1e0 fs/squashfs/export.c:57 Read of size 8 at addr ffff8880a36da378 by task syz-executor.4/7856 CPU: 0 PID: 7856 Comm: syz-executor.4 Not tainted 4.14.205-syzkaller #0 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+0x14b/0x1f1 lib/dump_stack.c:58 print_address_description.cold.6+0x9/0x1ca mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report.cold.7+0x11a/0x2d4 mm/kasan/report.c:409 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430 squashfs_export_iget+0x1aa/0x1e0 fs/squashfs/export.c:57 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 squashfs_fh_to_dentry+0x49/0x70 fs/squashfs/export.c:97 exportfs_decode_fh+0x10a/0x6df fs/exportfs/expfs.c:433 do_handle_to_path fs/fhandle.c:153 [inline] handle_to_path fs/fhandle.c:208 [inline] do_handle_open+0x25e/0x5c0 fs/fhandle.c:224 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready batman_adv: batadv0: Interface activated: batadv_slave_1 SYSC_open_by_handle_at fs/fhandle.c:266 [inline] SyS_open_by_handle_at+0xc/0x10 fs/fhandle.c:257 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45de59 RSP: 002b:00007f6e8cff3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000130 RAX: ffffffffffffffda RBX: 00000000000221c0 RCX: 000000000045de59 RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000005 RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffe9b9203ef R14: 00007f6e8cff49c0 R15: 000000000118bf2c Allocated by task 7856: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:551 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:536 __do_kmalloc mm/slab.c:3720 [inline] __kmalloc+0x15d/0x410 mm/slab.c:3729 kmalloc_array include/linux/slab.h:607 [inline] kcalloc include/linux/slab.h:618 [inline] squashfs_read_table+0x67/0x164 fs/squashfs/cache.c:430 squashfs_read_inode_lookup_table+0x40/0x90 fs/squashfs/export.c:144 squashfs_fill_super+0xd8b/0x1700 fs/squashfs/super.c:263 mount_bdev+0x26f/0x330 fs/super.c:1134 squashfs_mount+0x10/0x20 fs/squashfs/super.c:404 mount_fs+0x7f/0x269 fs/super.c:1237 vfs_kern_mount.part.9+0x58/0x3c0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x352/0x2af0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xb1/0xd0 fs/namespace.c:3072 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 7856: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xab/0x190 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcc/0x270 mm/slab.c:3815 squashfs_read_table+0xf7/0x164 fs/squashfs/cache.c:448 squashfs_read_inode_lookup_table+0x40/0x90 fs/squashfs/export.c:144 squashfs_fill_super+0xd8b/0x1700 fs/squashfs/super.c:263 mount_bdev+0x26f/0x330 fs/super.c:1134 squashfs_mount+0x10/0x20 fs/squashfs/super.c:404 mount_fs+0x7f/0x269 fs/super.c:1237 vfs_kern_mount.part.9+0x58/0x3c0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x352/0x2af0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xb1/0xd0 fs/namespace.c:3072 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb The buggy address belongs to the object at ffff8880a36da340 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 24 bytes to the right of 32-byte region [ffff8880a36da340, ffff8880a36da360) The buggy address belongs to the page: page:ffffea00028db680 count:1 mapcount:0 mapping:ffff8880a36da000 index:0xffff8880a36dafc1 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffff8880a36da000 ffff8880a36dafc1 000000010000003f raw: ffffea00027d8b60 ffffea0002b585e0 ffff8880b64001c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a36da200: 00 fc fc fc fc fc fc fc 00 fc fc fc fc fc fc fc ffff8880a36da280: 00 fc fc fc fc fc fc fc 00 fc fc fc fc fc fc fc >ffff8880a36da300: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ^ ffff8880a36da380: 00 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc ffff8880a36da400: fb fb fb fb fc fc fc fc 00 fc fc fc fc fc fc fc ==================================================================