Re: [syzbot] BUG: unable to handle kernel NULL pointer dereference in tiocsti

[syzbot <syzbot+032314e8d7de2bdb97f7@syzkaller.appspotmail.com>]

> #syz dup: BUG: unable to handle kernel NULL pointer dereference in 

can't find the dup bug

> gsmld_receive_buf
>
> On 24. 08. 22, 18:35, syzbot wrote:
>> Hello,
>> 
>> syzbot found the following issue on:
>> 
>> HEAD commit:    1c23f9e627a7 Linux 6.0-rc2
>> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
>> console output: https://syzkaller.appspot.com/x/log.txt?x=17eefdcb080000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=3045c937aad027f7
>> dashboard link: https://syzkaller.appspot.com/bug?extid=032314e8d7de2bdb97f7
>> compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
>> userspace arch: arm64
>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1190eb6b080000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16a1e50d080000
>> 
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+032314e8d7de2bdb97f7@syzkaller.appspotmail.com
>> 
>> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
>> Mem abort info:
>>    ESR = 0x0000000086000006
>>    EC = 0x21: IABT (current EL), IL = 32 bits
>>    SET = 0, FnV = 0
>>    EA = 0, S1PTW = 0
>>    FSC = 0x06: level 2 translation fault
>> user pgtable: 4k pages, 48-bit VAs, pgdp=000000010b28b000
>> [0000000000000000] pgd=080000010b411003, p4d=080000010b411003, pud=080000010b47b003, pmd=0000000000000000
>> Internal error: Oops: 86000006 [#1] PREEMPT SMP
>> Modules linked in:
>> CPU: 1 PID: 3028 Comm: syz-executor908 Not tainted 6.0.0-rc2-syzkaller-16440-g1c23f9e627a7 #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/20/2022
>> pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>> pc : 0x0
>> lr : gsmld_receive_buf+0x140/0x214 drivers/tty/n_gsm.c:2861
>> sp : ffff80000ffe3cb0
>> x29: ffff80000ffe3cc0 x28: 0000000000000000 x27: 0000000000000000
>> x26: 0000000000000000 x25: 0000000000000000 x24: ffff80000d937000
>> x23: ffff80000d681e40 x22: ffff0000cb2dc000 x21: ffff80000ffe3d21
>> x20: ffff80000c205988 x19: ffff80000ffe3d24 x18: 00000000000000c0
>> x17: ffff80000dd7a698 x16: 0000000000000000 x15: 0000000000000000
>> x14: 0000000000000000 x13: 0000000000000004 x12: ffff80000d681e78
>> x11: ff808000098e7e04 x10: 0000000000000000 x9 : ffff8000098e7e04
>> x8 : 0000000000000000 x7 : ffff8000098dcea4 x6 : 0000000000000000
>> x5 : ffff80000e087890 x4 : 0000000000000002 x3 : 0000000000000001
>> x2 : ffff80000ffe3d20 x1 : 0000000000000000 x0 : ffff0000cb2dc000
>> Call trace:
>>   0x0
>>   tiocsti+0x168/0x1c4 drivers/tty/tty_io.c:2293
>>   tty_ioctl+0x284/0x9f4 drivers/tty/tty_io.c:2692
>>   vfs_ioctl fs/ioctl.c:51 [inline]
>>   __do_sys_ioctl fs/ioctl.c:870 [inline]
>>   __se_sys_ioctl fs/ioctl.c:856 [inline]
>>   __arm64_sys_ioctl+0xd0/0x140 fs/ioctl.c:856
>>   __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
>>   invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
>>   el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
>>   do_el0_svc+0x48/0x154 arch/arm64/kernel/syscall.c:206
>>   el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:624
>>   el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:642
>>   el0t_64_sync+0x18c/0x190
>> Code: bad PC value
>> ---[ end trace 0000000000000000 ]---
>> 
>> 
>> ---
>> 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@googlegroups.com.
>> 
>> syzbot will keep track of this issue. See:
>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>> syzbot can test patches for this issue, for details see:
>> https://goo.gl/tpsmEJ#testing-patches
>
> -- 
> js
>
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