Doug, On 2018-08-03 04:46 AM, Wanlong Gao wrote: > Hi Martinand all folks, > > >> Recently we find a kernel panic with memory corruption caused by SG_IO ioctl(), >> and it can be easily reproduced by running following reproducer about >> minutes,any idea? > Which kernel? We've tested with 4.17.11 and 4.18.rc7 and both reproduced. > And what are the underlying devices (e.g. does /dev/sg0 refer to a SATA disk, > a real SCSI disk (SAS for example), USB mass storage, etc)? We tested in a qemu-kvm guest and the sg0 refer to a virtual SATA disk. > Also can you get a copy of the kernel panic? Since the call traces are different every time it reproduced, that I didn't paste the call trace or the vmcore, but this reproducer is very useful and I believe you can reproduce it easily using the following code. Thanks, Wanlong > Doug Gilbert > > C reproducer: > > // autogenerated by syzkaller (http://github.com/google/syzkaller) > > #define _GNU_SOURCE > > #include <endian.h> > > #include <sys/syscall.h> > > #include <unistd.h> > > #include <fcntl.h> > > #include <stdio.h> > > #include <string.h> > > #include <sys/stat.h> > > #include <stdint.h> > > #include <string.h> > > static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2) > > { > > if (a0 == 0xc || a0 == 0xb) { > > char buf[128]; > > sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1, > (uint8_t)a2); > > return open(buf, O_RDWR, 0); > > } else { > > char buf[1024]; > > char* hash; > > strncpy(buf, (char*)a0, sizeof(buf) - 1); > > buf[sizeof(buf) - 1] = 0; > > while ((hash = strchr(buf, '#'))) { > > *hash = '0' + (char)(a1 % 10); > > a1 /= 10; > > } > > return open(buf, a2, 0); > > } > > } > > static void execute_one(); > > extern unsigned long long procid; > > void loop() > > { > > while (1) { > > execute_one(); > > } > > } > > uint64_t r[1] = {0xffffffffffffffff}; > > void execute_one() > > { > > long res = 0; > > memcpy((void*)0x20000040, "/dev/sg#", 9); > > res = syz_open_dev(0x20000040, 0, 0); > > if (res != -1) > > r[0] = res; > > *(uint32_t*)0x200002c0 = 0x53; > > *(uint32_t*)0x200002c4 = 0; > > *(uint8_t*)0x200002c8 = 0xd; > > *(uint8_t*)0x200002c9 = 0; > > *(uint16_t*)0x200002ca = 0; > > *(uint32_t*)0x200002cc = 0x95; > > *(uint64_t*)0x200002d0 = 0x20000080; > > *(uint64_t*)0x200002d8 = 0x20000000; > > memcpy((void*)0x20000000, > "\x08\xf0\xa8\x77\xd3\xbe\x87\x5d\xda\x65\x79\x3f\xc7", 13); > > *(uint64_t*)0x200002e0 = 0x20000180; > > *(uint32_t*)0x200002e8 = 0x8001; > > *(uint32_t*)0x200002ec = 0x10024; > > *(uint32_t*)0x200002f0 = -1; > > *(uint64_t*)0x200002f4 = 0x20000280; > > *(uint8_t*)0x200002fc = 0; > > *(uint8_t*)0x200002fd = 0; > > *(uint8_t*)0x200002fe = 0; > > *(uint8_t*)0x200002ff = 0; > > *(uint16_t*)0x20000300 = 0; > > *(uint16_t*)0x20000302 = 0; > > *(uint32_t*)0x20000304 = 0; > > *(uint32_t*)0x20000308 = 0; > > *(uint32_t*)0x2000030c = 0; > > syscall(__NR_ioctl, r[0], 0x2285, 0x200002c0); > > } > > int main() > > { > > syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); > > for (;;) { > > loop(); > > } > > } >
