bisecting fixing commit since 5b7a52cd2eef952cee8a72512ef370bcdef46636 building syzkaller on 96e03c1c31a7f2e7f80b2d8b9f3df117df5030d1 testing commit 5b7a52cd2eef952cee8a72512ef370bcdef46636 with gcc (GCC) 8.4.1 20210217 kernel signature: f2bb2174dccb3649ba4347be8904ee52c236f9fc2c7f0810448284f69bf8e2a7 all runs: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry testing current HEAD cf256fbcbe347b7d0ff58fe2dfa382a156bd3694 testing commit cf256fbcbe347b7d0ff58fe2dfa382a156bd3694 with gcc (GCC) 8.4.1 20210217 kernel signature: 7a87ee6c05766a2355006d139df531fb20e80d57444b489037de6be324442a6d all runs: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry revisions tested: 2, total time: 27m43.657809202s (build: 19m37.535396708s, test: 7m35.22506707s) the crash still happens on HEAD commit msg: Linux 4.14.231 crash: KASAN: use-after-free Read in ext4_xattr_set_entry EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13929: comm syz-executor.2: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13954: comm syz-executor.5: corrupted xattr entries ================================================================== BUG: KASAN: use-after-free in ext4_xattr_set_entry+0x27be/0x3860 fs/ext4/xattr.c:1606 Read of size 4 at addr ffff8881c900a004 by task syz-executor.3/9938 CPU: 0 PID: 9938 Comm: syz-executor.3 Not tainted 4.14.231-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/0x1e7 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 mm/kasan/report.c:409 [inline] kasan_report.cold.7+0x11a/0x2d3 mm/kasan/report.c:393 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429 ext4_xattr_set_entry+0x27be/0x3860 fs/ext4/xattr.c:1606 ext4_xattr_ibody_set+0x70/0x290 fs/ext4/xattr.c:2245 ext4_xattr_set_handle+0x5ba/0xc50 fs/ext4/xattr.c:2402 ext4_xattr_set+0x1b4/0x2e0 fs/ext4/xattr.c:2514 ext4_xattr_trusted_set+0x1e/0x20 fs/ext4/xattr_trusted.c:37 __vfs_setxattr+0xd1/0x130 fs/xattr.c:150 __vfs_setxattr_noperm+0xe9/0x380 fs/xattr.c:181 __vfs_setxattr_locked+0x182/0x200 fs/xattr.c:239 vfs_setxattr+0xf5/0x260 fs/xattr.c:256 setxattr+0x1a0/0x250 fs/xattr.c:523 path_setxattr+0x130/0x150 fs/xattr.c:542 SYSC_setxattr fs/xattr.c:557 [inline] SyS_setxattr+0xf/0x20 fs/xattr.c:553 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x465849 RSP: 002b:00007fc4bfe58188 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc RAX: ffffffffffffffda RBX: 000000000055bfa8 RCX: 0000000000465849 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000020000100 RBP: 00000000004af675 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bfa8 R13: 00007ffd6fac94af R14: 00007fc4bfe58300 R15: 0000000000022000 The buggy address belongs to the page: page:ffffea0007240280 count:0 mapcount:0 mapping: (null) index:0x1 flags: 0x17ff00000000000() raw: 017ff00000000000 0000000000000000 0000000000000001 00000000ffffffff raw: ffffea0007238660 ffffea000723c220 0000000000000000 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881c9009f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881c9009f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8881c900a000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881c900a080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881c900a100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13968: comm syz-executor.3: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13924: comm syz-executor.1: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13941: comm syz-executor.2: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13962: comm syz-executor.0: corrupted xattr entries EXT4-fs: 117 callbacks suppressed EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs error: 84 callbacks suppressed EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13987: comm syz-executor.0: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13979: comm syz-executor.5: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13944: comm syz-executor.4: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_ibody_find:2198: inode #13985: comm syz-executor.3: corrupted in-inode xattr EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13933: comm syz-executor.1: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13987: comm syz-executor.0: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13976: comm syz-executor.2: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13944: comm syz-executor.4: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13933: comm syz-executor.1: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13937: comm syz-executor.3: corrupted xattr entries EXT4-fs: 119 callbacks suppressed EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs (sda1): Unrecognized mount option "fscontext=user_u" or missing value EXT4-fs error: 94 callbacks suppressed EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13996: comm syz-executor.1: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #14004: comm syz-executor.2: corrupted xattr entries EXT4-fs error (device sda1): ext4_xattr_set_entry:1609: inode #13991: comm syz-executor.0: corrupted xattr entries