bisecting fixing commit since 0c88e405c97ed1828443b67891e6d4bb6e56cd4e building syzkaller on 486f93ef445f733b35d844f33ba9edeb8423f5fa testing commit 0c88e405c97ed1828443b67891e6d4bb6e56cd4e with gcc (GCC) 8.1.0 kernel signature: f31b9b7d918f156a6bd65fbe0d3ef7cb88a278b84e46d96bef59731284ce675f all runs: crashed: KASAN: slab-out-of-bounds Read in squashfs_export_iget testing current HEAD 13d2ce42de8cb98ff952f8de6307f896203854c2 testing commit 13d2ce42de8cb98ff952f8de6307f896203854c2 with gcc (GCC) 8.1.0 kernel signature: 629d0459c761a9fd77534c97656ab615998bd805f004576bc0aabfae16dd60f9 all runs: crashed: KASAN: slab-out-of-bounds Read in squashfs_export_iget revisions tested: 2, total time: 23m58.23841567s (build: 17m37.128542148s, test: 5m39.701688217s) the crash still happens on HEAD commit msg: Linux 4.19.163 crash: KASAN: slab-out-of-bounds Read in squashfs_export_iget batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 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:3d) already exists on: batadv_slave_0 BUG: KASAN: slab-out-of-bounds in squashfs_inode_lookup fs/squashfs/export.c:57 [inline] BUG: KASAN: slab-out-of-bounds in squashfs_export_iget+0x22a/0x260 fs/squashfs/export.c:82 Read of size 8 at addr ffff888098330738 by task syz-executor.1/9838 CPU: 1 PID: 9838 Comm: syz-executor.1 Not tainted 4.19.163-syzkaller #0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! 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+0x17c/0x22a lib/dump_stack.c:118 print_address_description.cold.6+0x9/0x211 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x307 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 squashfs_inode_lookup fs/squashfs/export.c:57 [inline] squashfs_export_iget+0x22a/0x260 fs/squashfs/export.c:82 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! squashfs_fh_to_dentry+0x49/0x70 fs/squashfs/export.c:97 exportfs_decode_fh+0x119/0x669 fs/exportfs/expfs.c:433 do_handle_to_path fs/fhandle.c:152 [inline] handle_to_path fs/fhandle.c:207 [inline] do_handle_open+0x26c/0x5d0 fs/fhandle.c:223 __do_sys_open_by_handle_at fs/fhandle.c:265 [inline] __se_sys_open_by_handle_at fs/fhandle.c:256 [inline] __x64_sys_open_by_handle_at+0x71/0xb0 fs/fhandle.c:256 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45deb9 Code: 0d b4 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 b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fd6c2129c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000130 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 RAX: ffffffffffffffda RBX: 0000000000022240 RCX: 000000000045deb9 RDX: 0000000000490400 RSI: 0000000020000100 RDI: 0000000000000005 RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffc05708b6f R14: 00007fd6c212a9c0 R15: 000000000118bf2c Allocated by task 9838: save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:553 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:538 __do_kmalloc mm/slab.c:3727 [inline] __kmalloc+0x15d/0x3d0 mm/slab.c:3736 kmalloc_array include/linux/slab.h:637 [inline] kcalloc include/linux/slab.h:648 [inline] squashfs_read_table+0x68/0x165 fs/squashfs/cache.c:430 squashfs_read_inode_lookup_table+0x7c/0xd0 fs/squashfs/export.c:144 squashfs_fill_super+0xbcf/0x1a20 fs/squashfs/super.c:263 mount_bdev+0x26f/0x330 fs/super.c:1158 squashfs_mount+0x10/0x20 fs/squashfs/super.c:404 mount_fs+0x7f/0x2a2 fs/super.c:1261 vfs_kern_mount.part.11+0x58/0x3d0 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2469 [inline] do_mount+0x376/0x2710 fs/namespace.c:2799 ksys_mount+0xba/0xe0 fs/namespace.c:3015 __do_sys_mount fs/namespace.c:3029 [inline] __se_sys_mount fs/namespace.c:3026 [inline] __x64_sys_mount+0xb9/0x150 fs/namespace.c:3026 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9838: save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x13c/0x220 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 squashfs_read_table+0xf8/0x165 fs/squashfs/cache.c:448 squashfs_read_inode_lookup_table+0x7c/0xd0 fs/squashfs/export.c:144 squashfs_fill_super+0xbcf/0x1a20 fs/squashfs/super.c:263 mount_bdev+0x26f/0x330 fs/super.c:1158 squashfs_mount+0x10/0x20 fs/squashfs/super.c:404 mount_fs+0x7f/0x2a2 fs/super.c:1261 vfs_kern_mount.part.11+0x58/0x3d0 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2469 [inline] do_mount+0x376/0x2710 fs/namespace.c:2799 ksys_mount+0xba/0xe0 fs/namespace.c:3015 __do_sys_mount fs/namespace.c:3029 [inline] __se_sys_mount fs/namespace.c:3026 [inline] __x64_sys_mount+0xb9/0x150 fs/namespace.c:3026 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888098330700 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 24 bytes to the right of 32-byte region [ffff888098330700, ffff888098330720) The buggy address belongs to the page: page:ffffea000260cc00 count:1 mapcount:0 mapping:ffff88813bff61c0 index:0xffff888098330fc1 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffff88813bff4238 ffff88813bff4238 ffff88813bff61c0 raw: ffff888098330fc1 ffff888098330000 000000010000003c 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888098330600: 00 fc fc fc fc fc fc fc 00 fc fc fc fc fc fc fc ffff888098330680: 00 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc >ffff888098330700: fb fb fb fb fc fc fc fc 00 fc fc fc fc fc fc fc ^ ffff888098330780: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ffff888098330800: 00 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! ==================================================================