bisecting fixing commit since eb575cd5d7f60241d016fdd13a9e86d962093c9b building syzkaller on aba2b2fb3544d9e42991237c13d8cada421deda5 testing commit eb575cd5d7f60241d016fdd13a9e86d962093c9b compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 7245c9aa8127dff3c053b4024b092b5f70de5d1b3d1593d3d416f9ecd663a2db run #0: crashed: KASAN: use-after-free Read in __isofs_iget run #1: crashed: KASAN: use-after-free Read in __isofs_iget run #2: crashed: KASAN: use-after-free Read in __isofs_iget run #3: crashed: KASAN: use-after-free Read in __isofs_iget run #4: crashed: KASAN: use-after-free Read in __isofs_iget run #5: crashed: KASAN: use-after-free Read in __isofs_iget run #6: crashed: KASAN: use-after-free Read in __isofs_iget run #7: crashed: KASAN: use-after-free Read in __isofs_iget run #8: crashed: KASAN: use-after-free Read in __isofs_iget run #9: crashed: KASAN: use-after-free Read in __isofs_iget run #10: crashed: KASAN: use-after-free Read in __isofs_iget run #11: crashed: KASAN: out-of-bounds Read in __isofs_iget run #12: crashed: KASAN: use-after-free Read in __isofs_iget run #13: crashed: KASAN: use-after-free Read in __isofs_iget run #14: crashed: KASAN: use-after-free Read in __isofs_iget run #15: crashed: KASAN: use-after-free Read in __isofs_iget run #16: crashed: KASAN: use-after-free Read in __isofs_iget run #17: crashed: KASAN: use-after-free Read in __isofs_iget run #18: crashed: KASAN: use-after-free Read in __isofs_iget run #19: crashed: KASAN: use-after-free Read in __isofs_iget testing current HEAD 59456c9cc40c8f75b5a7efa0fe1f211d9c6fcaf1 testing commit 59456c9cc40c8f75b5a7efa0fe1f211d9c6fcaf1 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 41524da8f041a17e1ea28871429745fd53064f5c33dc2acc728d224419137c95 all runs: crashed: KASAN: use-after-free Read in __isofs_iget revisions tested: 2, total time: 28m30.477745603s (build: 21m17.360371449s, test: 6m43.807778547s) the crash still happens on HEAD commit msg: Linux 4.19.204 crash: KASAN: use-after-free Read in __isofs_iget IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready ================================================================== BUG: KASAN: use-after-free in isofs_read_inode fs/isofs/inode.c:1355 [inline] BUG: KASAN: use-after-free in __isofs_iget+0x1c58/0x2010 fs/isofs/inode.c:1555 Read of size 1 at addr ffff888080840015 by task syz-executor.2/10004 CPU: 0 PID: 10004 Comm: syz-executor.2 Not tainted 4.19.204-syzkaller #0 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/0x226 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 mm/kasan/report.c:412 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:396 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 isofs_read_inode fs/isofs/inode.c:1355 [inline] __isofs_iget+0x1c58/0x2010 fs/isofs/inode.c:1555 isofs_iget fs/isofs/isofs.h:134 [inline] isofs_export_iget.part.1+0x12/0x80 fs/isofs/export.c:29 isofs_export_iget fs/isofs/export.c:170 [inline] isofs_fh_to_dentry+0xc7/0x110 fs/isofs/export.c:170 exportfs_decode_fh+0x119/0x640 fs/exportfs/expfs.c:433 Bluetooth: hci1: command 0x0419 tx timeout 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: 0033:0x4665d9 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:00007fae72f08188 EFLAGS: 00000246 ORIG_RAX: 0000000000000130 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9 RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000005 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffde9793b7f R14: 00007fae72f08300 R15: 0000000000022000 The buggy address belongs to the page: page:ffffea0002021000 count:0 mapcount:0 mapping:0000000000000000 index:0x1 flags: 0xfff00000000000() raw: 00fff00000000000 ffffea0002021048 ffff8880ba22ea08 0000000000000000 raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808083ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88808083ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888080840000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888080840080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888080840100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== ---------------- Code disassembly (best guess), 1 bytes skipped: 0: ff c3 inc %ebx 2: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 9: 00 00 00 c: 0f 1f 40 00 nopl 0x0(%rax) 10: 48 89 f8 mov %rdi,%rax 13: 48 89 f7 mov %rsi,%rdi 16: 48 89 d6 mov %rdx,%rsi 19: 48 89 ca mov %rcx,%rdx 1c: 4d 89 c2 mov %r8,%r10 1f: 4d 89 c8 mov %r9,%r8 22: 4c 8b 4c 24 08 mov 0x8(%rsp),%r9 27: 0f 05 syscall 29: 48 3d 01 f0 ff ff cmp $0xfffffffffffff001,%rax <-- trapping instruction 2f: 73 01 jae 0x32 31: c3 retq 32: 48 c7 c1 bc ff ff ff mov $0xffffffffffffffbc,%rcx 39: f7 d8 neg %eax 3b: 64 89 01 mov %eax,%fs:(%rcx) 3e: 48 rex.W