bisecting fixing commit since f8ad8187c3b536ee2b10502a8340c014204a1af0 building syzkaller on 52e3731913ab2677be27c29ed8142b04e8f28521 testing commit f8ad8187c3b536ee2b10502a8340c014204a1af0 with gcc (GCC) 10.2.1 20210217 kernel signature: 1ae4ca6c61b7517e1ab76ca2845f8b8eeb14eed2597d2acd10ce9ac3edf5a682 run #0: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #1: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #2: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #3: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #4: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #5: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #6: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #7: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #8: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #9: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #10: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #11: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #12: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #13: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #14: crashed: KASAN: out-of-bounds Read in ext4_xattr_set_entry run #15: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #16: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #17: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #18: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #19: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry testing current HEAD 2a1d7946fa53cea2083e5981ff55a8176ab2be6b testing commit 2a1d7946fa53cea2083e5981ff55a8176ab2be6b with gcc (GCC) 10.2.1 20210217 kernel signature: 70920ccfc29523399736b524263237f1d8a6df3697ea3e61b61bd61a5450903d run #0: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #1: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #2: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #3: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #4: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #5: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #6: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry run #7: crashed: KASAN: out-of-bounds Read in ext4_xattr_set_entry run #8: crashed: KASAN: out-of-bounds Read in ext4_xattr_set_entry run #9: crashed: KASAN: use-after-free Read in ext4_xattr_set_entry revisions tested: 2, total time: 20m27.504877969s (build: 11m2.074772033s, test: 8m46.229652584s) the crash still happens on HEAD commit msg: Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm crash: KASAN: use-after-free Read in ext4_xattr_set_entry ================================================================== BUG: KASAN: use-after-free in ext4_xattr_set_entry+0xc14/0x3750 fs/ext4/xattr.c:1589 Read of size 4 at addr ffff88803a553004 by task syz-executor.2/14944 CPU: 0 PID: 14944 Comm: syz-executor.2 Not tainted 5.12.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x93/0xc2 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232 __kasan_report mm/kasan/report.c:399 [inline] kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416 ext4_xattr_set_entry+0xc14/0x3750 fs/ext4/xattr.c:1589 ext4_xattr_ibody_set+0x60/0x260 fs/ext4/xattr.c:2227 ext4_xattr_set_handle+0x71c/0x10e0 fs/ext4/xattr.c:2384 ext4_xattr_set+0x11d/0x2c0 fs/ext4/xattr.c:2497 __vfs_setxattr+0xdb/0x130 fs/xattr.c:180 __vfs_setxattr_noperm+0xee/0x480 fs/xattr.c:214 vfs_setxattr+0x111/0x2d0 fs/xattr.c:300 setxattr+0x157/0x260 fs/xattr.c:573 path_setxattr+0x13c/0x170 fs/xattr.c:593 __do_sys_setxattr fs/xattr.c:609 [inline] __se_sys_setxattr fs/xattr.c:605 [inline] __x64_sys_setxattr+0xbb/0x150 fs/xattr.c:605 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x465b09 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007feeff5c9188 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000020000100 RBP: 00000000004b069f R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007fff3099ccff R14: 00007feeff5c9300 R15: 0000000000022000 The buggy address belongs to the page: page:000000004e38513d refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1 pfn:0x3a553 flags: 0xfff00000000000() raw: 00fff00000000000 ffffea0000a7ddc8 ffffea0000e96388 0000000000000000 raw: 0000000000000001 0000000000000000 00000000ffffff7f 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88803a552f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88803a552f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88803a553000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88803a553080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88803a553100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================