syzbot has found a reproducer for the following issue on: HEAD commit: 77dd11439b86 Merge tag 'drm-fixes-2021-08-27' of git://ano.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10636bde300000 kernel config: https://syzkaller.appspot.com/x/.config?x=2fd902af77ff1e56 dashboard link: https://syzkaller.appspot.com/bug?extid=d1e3b1d92d25abf97943 compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=126d084d300000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16216eb1300000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+d1e3b1d92d25abf97943@xxxxxxxxxxxxxxxxxxxxxxxxx general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 8435 Comm: syz-executor272 Not tainted 5.14.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:memchr+0x2f/0x70 lib/string.c:1054 Code: 41 54 53 48 89 d3 41 89 f7 45 31 f6 49 bc 00 00 00 00 00 fc ff df 0f 1f 44 00 00 48 85 db 74 3b 48 89 fd 48 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 75 0f 48 ff cb 48 8d 7d 01 44 38 7d 00 75 db RSP: 0018:ffffc9000d9f7d08 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88801c1f3880 RDX: 0000000000000001 RSI: 000000000000002c RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffff81e3db46 R09: ffffffff81e3d8e2 R10: 0000000000000002 R11: ffff88801c1f3880 R12: dffffc0000000000 R13: 1ffff92001b3efcc R14: 0000000000000000 R15: 000000000000002c FS: 0000000000deb300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000044 CR3: 0000000037173000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: legacy_parse_param+0x49b/0x810 fs/fs_context.c:555 vfs_parse_fs_param+0x1df/0x460 fs/fs_context.c:146 vfs_fsconfig_locked fs/fsopen.c:265 [inline] __do_sys_fsconfig fs/fsopen.c:439 [inline] __se_sys_fsconfig+0xba9/0xff0 fs/fsopen.c:314 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x43ee69 Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc5e9e0b98 EFLAGS: 00000246 ORIG_RAX: 00000000000001af RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043ee69 RDX: 0000000020000080 RSI: 0000000000000001 RDI: 0000000000000003 RBP: 0000000000402e50 R08: 0000000000000000 R09: 0000000000400488 R10: 00000000200000c0 R11: 0000000000000246 R12: 0000000000402ee0 R13: 0000000000000000 R14: 00000000004ac018 R15: 0000000000400488 Modules linked in: ---[ end trace 74baf661f3b47b0a ]--- RIP: 0010:memchr+0x2f/0x70 lib/string.c:1054 Code: 41 54 53 48 89 d3 41 89 f7 45 31 f6 49 bc 00 00 00 00 00 fc ff df 0f 1f 44 00 00 48 85 db 74 3b 48 89 fd 48 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 75 0f 48 ff cb 48 8d 7d 01 44 38 7d 00 75 db RSP: 0018:ffffc9000d9f7d08 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88801c1f3880 RDX: 0000000000000001 RSI: 000000000000002c RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffff81e3db46 R09: ffffffff81e3d8e2 R10: 0000000000000002 R11: ffff88801c1f3880 R12: dffffc0000000000 R13: 1ffff92001b3efcc R14: 0000000000000000 R15: 000000000000002c FS: 0000000000deb300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fed5f8146c0 CR3: 0000000037173000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 41 54 push %r12 2: 53 push %rbx 3: 48 89 d3 mov %rdx,%rbx 6: 41 89 f7 mov %esi,%r15d 9: 45 31 f6 xor %r14d,%r14d c: 49 bc 00 00 00 00 00 movabs $0xdffffc0000000000,%r12 13: fc ff df 16: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 1b: 48 85 db test %rbx,%rbx 1e: 74 3b je 0x5b 20: 48 89 fd mov %rdi,%rbp 23: 48 89 f8 mov %rdi,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 0f b6 04 20 movzbl (%rax,%r12,1),%eax <-- trapping instruction 2f: 84 c0 test %al,%al 31: 75 0f jne 0x42 33: 48 ff cb dec %rbx 36: 48 8d 7d 01 lea 0x1(%rbp),%rdi 3a: 44 38 7d 00 cmp %r15b,0x0(%rbp) 3e: 75 db jne 0x1b
