On Fri, 17 Jun 2022 00:04:23 -0700 syzbot <syzbot+4d875b4d2e2b60bae9b4@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: c6d7e3b385f1 Add linux-next specific files for 20220616 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=10d9fb1bf00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=9d495405e4a98620 > dashboard link: https://syzkaller.appspot.com/bug?extid=4d875b4d2e2b60bae9b4 > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+4d875b4d2e2b60bae9b4@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:71 [inline] > BUG: KASAN: null-ptr-deref in test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] > BUG: KASAN: null-ptr-deref in hugepage_vma_check+0x8e/0x750 mm/huge_memory.c:82 > Read of size 8 at addr 00000000000005a8 by task syz-executor.5/21978 vma->vm_mm is NULL in show_smap->hugepage_vma_check(). Perhaps m_start() should be checking the mm after taking mmap_read_lock() instead of before? Matthew, you mucked with it last ;) Can you please take a look? > CPU: 0 PID: 21978 Comm: syz-executor.5 Not tainted 5.19.0-rc2-next-20220616-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > <TASK> > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 > kasan_report+0xbe/0x1f0 mm/kasan/report.c:495 > check_region_inline mm/kasan/generic.c:183 [inline] > kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 > instrument_atomic_read include/linux/instrumented.h:71 [inline] > test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] > hugepage_vma_check+0x8e/0x750 mm/huge_memory.c:82 > show_smap+0x1c6/0x470 fs/proc/task_mmu.c:866 > traverse.part.0+0xcf/0x5f0 fs/seq_file.c:111 > traverse fs/seq_file.c:101 [inline] > seq_read_iter+0x90f/0x1280 fs/seq_file.c:195 > seq_read+0x337/0x4b0 fs/seq_file.c:162 > do_loop_readv_writev fs/read_write.c:763 [inline] > do_loop_readv_writev fs/read_write.c:750 [inline] > do_iter_read+0x4f8/0x750 fs/read_write.c:805 > vfs_readv+0xe5/0x150 fs/read_write.c:923 > do_preadv fs/read_write.c:1015 [inline] > __do_sys_preadv fs/read_write.c:1065 [inline] > __se_sys_preadv fs/read_write.c:1060 [inline] > __x64_sys_preadv+0x22b/0x310 fs/read_write.c:1060 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > RIP: 0033:0x7f5c1d889109 > 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 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f5c1ea69168 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 > RAX: ffffffffffffffda RBX: 00007f5c1d99bf60 RCX: 00007f5c1d889109 > RDX: 0000000000000001 RSI: 00000000200006c0 RDI: 0000000000000005 > RBP: 00007f5c1d8e305d R08: 0000000000000000 R09: 0000000000000000 > R10: 00000000fffffffe R11: 0000000000000246 R12: 0000000000000000 > R13: 00007ffd8514b43f R14: 00007f5c1ea69300 R15: 0000000000022000 > </TASK> > ================================================================== > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
