syzbot

kernel panic at kern/src/ns/fs_file.c:431, from core 0: assertion failed: buf == buf_end
Stack Backtrace on Core 0:
#01 [<0xffffffffc200a33c>] in backtrace at src/kdebug.c:229
#02 [<0xffffffffc2009acd>] in _panic at src/init.c:267
#03 [<0xffffffffc203915b>] in fs_file_write at src/ns/fs_file.c:431
#04 [<0xffffffffc20440d6>] in tree_chan_write at src/ns/tree_file.c:1014
#05 [<0xffffffffc2040371>] in rwrite at src/ns/sysfile.c:1124
#06 [<0xffffffffc204058b>] in syswrite at src/ns/sysfile.c:1142
#07 [<0xffffffffc2056951>] in sys_write at src/syscall.c:1704
#08 [<0xffffffffc2059f09>] in syscall at src/syscall.c:2465
#09 [<0xffffffffc205a0d4>] in run_local_syscall at src/syscall.c:2500
#10 [<0xffffffffc205a609>] in prep_syscalls at src/syscall.c:2520
#11 [<0xffffffffc20abc0a>] in sysenter_callwrapper at arch/x86/trap.c:854