syzbot

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Unable to handle kernel NULL pointer dereference at virtual address 00000000
[00000000] *pgd=85387003, *pmd=fe74e003
Internal error: Oops: 80000207 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 1 PID: 8604 Comm: syz-executor.1 Not tainted 6.0.0-rc3-syzkaller #0
Hardware name: ARM-Versatile Express
PC is at 0x0
LR is at gsmld_receive_buf+0xc0/0x15c drivers/tty/n_gsm.c:2861
pc : [<00000000>]    lr : [<808eaab4>]    psr: 60000013
sp : dfa2de28  ip : 826efeb0  fp : dfa2de6c
r10: 81de5c68  r9 : 825d5140  r8 : dfa2de7c
r7 : 84e11000  r6 : 00000000  r5 : dfa2de7d  r4 : dfa2de7c
r3 : 00000000  r2 : dfa2de7c  r1 : 00000000  r0 : 84e11000
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 30c5387d  Table: 8502cb40  DAC: 00000000
Register r0 information: slab kmalloc-512 start 84e11000 pointer offset 0 size 512
Register r1 information: NULL pointer
Register r2 information: 2-page vmalloc region starting at 0xdfa2c000 allocated at kernel_clone+0x9c/0x440 kernel/fork.c:2673
Register r3 information: NULL pointer
Register r4 information: 2-page vmalloc region starting at 0xdfa2c000 allocated at kernel_clone+0x9c/0x440 kernel/fork.c:2673
Register r5 information: 2-page vmalloc region starting at 0xdfa2c000 allocated at kernel_clone+0x9c/0x440 kernel/fork.c:2673
Register r6 information: NULL pointer
Register r7 information: slab kmalloc-512 start 84e11000 pointer offset 0 size 512
Register r8 information: 2-page vmalloc region starting at 0xdfa2c000 allocated at kernel_clone+0x9c/0x440 kernel/fork.c:2673
Register r9 information: non-slab/vmalloc memory
Register r10 information: non-slab/vmalloc memory
Register r11 information: 2-page vmalloc region starting at 0xdfa2c000 allocated at kernel_clone+0x9c/0x440 kernel/fork.c:2673
Register r12 information: non-slab/vmalloc memory
Process syz-executor.1 (pid: 8604, stack limit = 0xdfa2c000)
Stack: (0xdfa2de28 to 0xdfa2e000)
de20:                   8067b314 0b6d83e6 84e00c00 84e00c18 81de5bc0 84e00c00
de40: 85048900 00000000 85363540 84e00c00 808ea9f4 85048900 20000000 84e00c00
de60: dfa2df14 dfa2de70 808dcfac 808eaa00 00000001 82b20450 00000054 85048900
de80: 00000004 00000036 dfa2dee4 dfa2de98 8068af1c 80680e64 00000001 00000054
dea0: 00000012 dfa2deb4 83ea59d0 82c3c770 dfa25412 0b6d830b dfa2dea8 81f4cdc0
dec0: 20000000 0b6d83e6 81f4c0dc 20000000 85048900 00005412 dfa2def4 dfa2dee8
dee0: 8068b020 0b6d83e6 dfa2df14 00005412 00000000 85048901 20000000 85048900
df00: 00000004 82b20450 dfa2dfa4 dfa2df18 804b9814 808dc804 dfa2df34 83242f00
df20: 83243620 00000002 ddde36e8 5bb3b000 822a86f0 83242f00 00000002 ddde36e8
df40: dfa2df5c dfa2df50 8172d110 8172cfd8 dfa2df84 dfa2df60 8172cbe8 8172d100
df60: 60000013 00000000 0012bfd0 00000036 60000010 0b6d83e6 dfa2df9c 00000000
df80: 00000000 0012bfd0 00000036 80200288 83242f00 00000036 00000000 dfa2dfa8
dfa0: 80200060 804b9710 00000000 00000000 00000004 00005412 20000000 00000000
dfc0: 00000000 00000000 0012bfd0 00000036 7e9763b2 76f096d0 7e976544 76f0920c
dfe0: 76f09020 76f09010 00016420 0004c150 60000010 00000004 00000000 00000000
Backtrace: 
[<808ea9f4>] (gsmld_receive_buf) from [<808dcfac>] (tiocsti drivers/tty/tty_io.c:2293 [inline])
[<808ea9f4>] (gsmld_receive_buf) from [<808dcfac>] (tty_ioctl+0x7b4/0xa6c drivers/tty/tty_io.c:2692)
 r10:84e00c00 r9:20000000 r8:85048900 r7:808ea9f4 r6:84e00c00 r5:85363540
 r4:00000000
[<808dc7f8>] (tty_ioctl) from [<804b9814>] (vfs_ioctl fs/ioctl.c:51 [inline])
[<808dc7f8>] (tty_ioctl) from [<804b9814>] (do_vfs_ioctl fs/ioctl.c:830 [inline])
[<808dc7f8>] (tty_ioctl) from [<804b9814>] (__do_sys_ioctl fs/ioctl.c:868 [inline])
[<808dc7f8>] (tty_ioctl) from [<804b9814>] (sys_ioctl+0x110/0xa74 fs/ioctl.c:856)
 r10:82b20450 r9:00000004 r8:85048900 r7:20000000 r6:85048901 r5:00000000
 r4:00005412
[<804b9704>] (sys_ioctl) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:64)
Exception stack(0xdfa2dfa8 to 0xdfa2dff0)
dfa0:                   00000000 00000000 00000004 00005412 20000000 00000000
dfc0: 00000000 00000000 0012bfd0 00000036 7e9763b2 76f096d0 7e976544 76f0920c
dfe0: 76f09020 76f09010 00016420 0004c150
 r10:00000036 r9:83242f00 r8:80200288 r7:00000036 r6:0012bfd0 r5:00000000
 r4:00000000
Code: bad PC value
---[ end trace 0000000000000000 ]---