bisecting fixing commit since 258f0cf7ac3b788a14c0d01aab3c4aea02f8c86e building syzkaller on 6d882fd26c01d118a584b2a3aecd5f08fa5e11e1 testing commit 258f0cf7ac3b788a14c0d01aab3c4aea02f8c86e with gcc (GCC) 8.1.0 kernel signature: 8e11c543d94b3a0c6ace9a653fbe4cf58fc7b2efd7cb0acd6cf48154effd65e9 run #0: crashed: KASAN: use-after-free Read in get_block run #1: crashed: KASAN: use-after-free Read in get_block run #2: crashed: KASAN: slab-out-of-bounds Read in get_block run #3: crashed: KASAN: slab-out-of-bounds Read in get_block run #4: crashed: KASAN: use-after-free Read in get_block run #5: crashed: KASAN: use-after-free Read in get_block run #6: crashed: KASAN: slab-out-of-bounds Read in V1_minix_truncate run #7: crashed: KASAN: slab-out-of-bounds Read in V1_minix_truncate run #8: crashed: KASAN: use-after-free Read in get_block run #9: crashed: KASAN: slab-out-of-bounds Read in get_block testing current HEAD 3fc898571b974f9a05e4e5c1fe17b18548207091 testing commit 3fc898571b974f9a05e4e5c1fe17b18548207091 with gcc (GCC) 8.1.0 kernel signature: 55ebafecd87c57bd2eafa2399dea5c98b81f436d8ee7333436bf1610185022d5 run #0: crashed: KASAN: slab-out-of-bounds Read in get_block run #1: crashed: KASAN: slab-out-of-bounds Read in get_block run #2: crashed: KASAN: slab-out-of-bounds Read in get_block run #3: crashed: KASAN: slab-out-of-bounds Read in get_block run #4: crashed: KASAN: use-after-free Read in get_block run #5: crashed: KASAN: slab-out-of-bounds Read in get_block run #6: crashed: KASAN: use-after-free Read in get_block run #7: crashed: KASAN: slab-out-of-bounds Read in get_block run #8: crashed: KASAN: use-after-free Read in get_block run #9: crashed: KASAN: use-after-free Read in get_block revisions tested: 2, total time: 24m40.446785742s (build: 17m38.049777509s, test: 6m29.743858944s) the crash still happens on HEAD commit msg: Linux 4.19.128 crash: KASAN: use-after-free Read in get_block batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 MINIX-fs: mounting unchecked file system, running fsck is recommended batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! Process accounting resumed ================================================================== BUG: KASAN: use-after-free in add_chain fs/minix/itree_common.c:14 [inline] BUG: KASAN: use-after-free in get_branch fs/minix/itree_common.c:52 [inline] BUG: KASAN: use-after-free in get_block+0xebc/0x1120 fs/minix/itree_common.c:160 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 Read of size 2 at addr ffff88807663b644 by task syz-executor.1/7823 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! CPU: 1 PID: 7823 Comm: syz-executor.1 Not tainted 4.19.128-syzkaller #0 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x123/0x177 lib/dump_stack.c:118 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:431 add_chain fs/minix/itree_common.c:14 [inline] get_branch fs/minix/itree_common.c:52 [inline] get_block+0xebc/0x1120 fs/minix/itree_common.c:160 V1_minix_get_block+0x9/0x10 fs/minix/itree_v1.c:56 minix_get_block+0xa7/0x110 fs/minix/inode.c:379 __block_write_begin_int+0x39b/0x1a80 fs/buffer.c:1978 __block_write_begin fs/buffer.c:2028 [inline] block_write_begin+0x48/0x260 fs/buffer.c:2087 minix_write_begin+0x2f/0xc0 fs/minix/inode.c:415 generic_perform_write+0x289/0x480 mm/filemap.c:3162 __generic_file_write_iter+0x201/0x580 mm/filemap.c:3287 generic_file_write_iter+0x29f/0x650 mm/filemap.c:3315 call_write_iter include/linux/fs.h:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x443/0x890 fs/read_write.c:487 IPv6: ADDRCONF(NETDEV_UP): batadv_slave_0: link is not ready batman_adv: batadv0: Interface activated: batadv_slave_0 IPv6: ADDRCONF(NETDEV_UP): macvlan1: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth0_macvtap: link is not ready __kernel_write+0xe4/0x350 fs/read_write.c:506 IPv6: ADDRCONF(NETDEV_UP): veth1_macvtap: link is not ready do_acct_process+0xa5e/0xeb0 kernel/acct.c:520 acct_pin_kill+0x29/0x100 kernel/acct.c:174 pin_kill+0x140/0x640 fs/fs_pin.c:50 acct_on+0x4f6/0x6c0 kernel/acct.c:254 __do_sys_acct kernel/acct.c:286 [inline] __se_sys_acct kernel/acct.c:273 [inline] __x64_sys_acct+0x7a/0x170 kernel/acct.c:273 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe 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:00007f3e9fce4c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a3 RAX: ffffffffffffffda RBX: 00000000004d9540 RCX: 000000000045ca29 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000480 RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000001c R14: 00000000004c2dc8 R15: 00007f3e9fce56d4 The buggy address belongs to the page: page:ffffea0001d98ec0 count:0 mapcount:0 mapping:0000000000000000 index:0x1 flags: 0xfffe0000000000() raw: 00fffe0000000000 ffffea0001d98a88 ffffea0001d97848 0000000000000000 raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88807663b500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88807663b580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88807663b600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88807663b680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88807663b700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================