[Linux kernel bug] WARNING in static_key_slow_inc_cpuslocked
From: Sam Sun
Date: Sun Jun 09 2024 - 02:33:21 EST
Dear developers and maintainers,
We encountered a kernel bug while using our modified
syzkaller. It was tested against the latest upstream kernel.
Kernel crash log is listed below.
```
[ 82.310798][ T8020] ------------[ cut here ]------------
[ 82.311236][ T8020] kernel BUG at arch/x86/kernel/jump_label.c:73!
[ 82.311761][ T8020] Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
[ 82.312331][ T8020] CPU: 0 PID: 8020 Comm: static_key_slow Not
tainted 6.10.0-rc2-00366-g771ed66105de 3
[ 82.313044][ T8020] Hardware name: QEMU Standard PC (i440FX + PIIX,
1996), BIOS 1.13.0-1ubuntu1.1 04/04
[ 82.313778][ T8020] RIP: 0010:__jump_label_patch+0x456/0x480
[ 82.314223][ T8020] Code: e8 af a1 5d 00 48 c7 c7 40 01 86 8b 48 8b
0c 24 48 89 ce 48 89 ca 4d 89 e8 4f
[ 82.315745][ T8020] RSP: 0018:ffffc9000f9cf980 EFLAGS: 00010292
[ 82.316204][ T8020] RAX: 000000000000008b RBX: 0000000000000085
RCX: 218564eba7c06800
[ 82.316813][ T8020] RDX: 0000000000000000 RSI: 0000000080000000
RDI: 0000000000000000
[ 82.317396][ T8020] RBP: ffffc9000f9cfac0 R08: ffffffff817176dc
R09: 1ffff92001f39ed0
[ 82.317987][ T8020] R10: dffffc0000000000 R11: fffff52001f39ed1
R12: 0000000000000001
[ 82.318548][ T8020] R13: ffffffff8b862901 R14: ffffffff90fbe8c0
R15: ffffffff8b862901
[ 82.319116][ T8020] FS: 00007f04610bc540(0000)
GS:ffff88802c800000(0000) knlGS:0000000000000000
[ 82.319808][ T8020] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 82.320308][ T8020] CR2: 00007f0460fd9650 CR3: 000000004a16a000
CR4: 0000000000750ef0
[ 82.320883][ T8020] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[ 82.321460][ T8020] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
[ 82.322004][ T8020] PKRU: 55555554
[ 82.322269][ T8020] Call Trace:
[ 82.322515][ T8020] <TASK>
[ 82.322729][ T8020] ? __die_body+0x88/0xe0
[ 82.323043][ T8020] ? die+0xcf/0x110
[ 82.323322][ T8020] ? do_trap+0x155/0x3a0
[ 82.323625][ T8020] ? __jump_label_patch+0x456/0x480
[ 82.324009][ T8020] ? do_error_trap+0x1dc/0x2a0
[ 82.324371][ T8020] ? __jump_label_patch+0x456/0x480
[ 82.324774][ T8020] ? do_int3+0x50/0x50
[ 82.325088][ T8020] ? handle_invalid_op+0x34/0x40
[ 82.325445][ T8020] ? __jump_label_patch+0x456/0x480
[ 82.325815][ T8020] ? exc_invalid_op+0x34/0x50
[ 82.326156][ T8020] ? asm_exc_invalid_op+0x1a/0x20
[ 82.326533][ T8020] ? __wake_up_klogd+0xcc/0x100
[ 82.326879][ T8020] ? __jump_label_patch+0x456/0x480
[ 82.327249][ T8020] ? cr4_update_pce+0xf/0x80
[ 82.327601][ T8020] ? arch_jump_label_transform_queue+0xf0/0xf0
[ 82.328047][ T8020] ? cr4_update_pce+0xf/0x80
[ 82.328380][ T8020] ? cr4_update_pce+0x1e/0x80
[ 82.328717][ T8020] ? cr4_update_pce+0x11/0x80
[ 82.329052][ T8020] ? read_lock_is_recursive+0x20/0x20
[ 82.329466][ T8020] ? __static_key_slow_dec_cpuslocked+0xb0/0x140
[ 82.329966][ T8020] ? text_poke_queue+0x46/0x180
[ 82.330329][ T8020] arch_jump_label_transform_queue+0x63/0xf0
[ 82.330742][ T8020] __jump_label_update+0x18b/0x3b0
[ 82.331101][ T8020] __static_key_slow_dec_cpuslocked+0xe9/0x140
[ 82.331519][ T8020] static_key_slow_dec+0x50/0xa0
[ 82.331873][ T8020] set_attr_rdpmc+0x193/0x270
[ 82.332179][ T8020] ? get_attr_rdpmc+0x30/0x30
[ 82.332511][ T8020] ? sysfs_kf_write+0x18d/0x2b0
[ 82.332832][ T8020] ? sysfs_kf_read+0x370/0x370
[ 82.333159][ T8020] kernfs_fop_write_iter+0x3ab/0x500
[ 82.333531][ T8020] vfs_write+0xa8b/0xd00
[ 82.333812][ T8020] ? kernfs_fop_read_iter+0x640/0x640
[ 82.334234][ T8020] ? kernel_write+0x330/0x330
[ 82.334598][ T8020] ? do_sys_openat2+0x16b/0x1c0
[ 82.334949][ T8020] ? do_sys_open+0x230/0x230
[ 82.335310][ T8020] ? __up_read+0x2bb/0x6a0
[ 82.335633][ T8020] ksys_write+0x17b/0x2a0
[ 82.335966][ T8020] ? __ia32_sys_read+0x90/0x90
[ 82.336333][ T8020] ? do_syscall_64+0xa5/0x230
[ 82.336656][ T8020] do_syscall_64+0xe2/0x230
[ 82.336983][ T8020] ? clear_bhb_loop+0x25/0x80
[ 82.337289][ T8020] entry_SYSCALL_64_after_hwframe+0x67/0x6f
[ 82.337692][ T8020] RIP: 0033:0x7f0460fd2473
[ 82.337987][ T8020] Code: 8b 15 21 2a 0e 00 f7 d8 64 89 02 48 c7 c0
ff ff ff ff eb b7 0f 1f 00 64 8b 08
[ 82.339230][ T8020] RSP: 002b:00007ffc46fb3058 EFLAGS: 00000246
ORIG_RAX: 0000000000000001
[ 82.339804][ T8020] RAX: ffffffffffffffda RBX: 0000000000000000
RCX: 00007f0460fd2473
[ 82.340331][ T8020] RDX: 0000000000000002 RSI: 00007ffc46fb3090
RDI: 0000000000000004
[ 82.340852][ T8020] RBP: 00007ffc46fb3cb0 R08: 000000000000000f
R09: 0072736d2f232f75
[ 82.341353][ T8020] R10: 0000000000000000 R11: 0000000000000246
R12: 00005615dc1dd1c0
[ 82.341853][ T8020] R13: 0000000000000000 R14: 0000000000000000
R15: 0000000000000000
[ 82.342364][ T8020] </TASK>
[ 82.342554][ T8020] Modules linked in:
[ 82.342875][ T8020] ---[ end trace 0000000000000000 ]---
[ 82.343230][ T8020] RIP: 0010:__jump_label_patch+0x456/0x480
[ 82.343668][ T8020] Code: e8 af a1 5d 00 48 c7 c7 40 01 86 8b 48 8b
0c 24 48 89 ce 48 89 ca 4d 89 e8 4f
[ 82.345750][ T8020] RSP: 0018:ffffc9000f9cf980 EFLAGS: 00010292
[ 82.346161][ T8020] RAX: 000000000000008b RBX: 0000000000000085
RCX: 218564eba7c06800
[ 82.346657][ T8020] RDX: 0000000000000000 RSI: 0000000080000000
RDI: 0000000000000000
[ 82.347391][ T8020] RBP: ffffc9000f9cfac0 R08: ffffffff817176dc
R09: 1ffff92001f39ed0
[ 82.347901][ T8020] R10: dffffc0000000000 R11: fffff52001f39ed1
R12: 0000000000000001
[ 82.348652][ T8020] R13: ffffffff8b862901 R14: ffffffff90fbe8c0
R15: ffffffff8b862901
[ 82.349173][ T8020] FS: 00007f04610bc540(0000)
GS:ffff88802c800000(0000) knlGS:0000000000000000
[ 82.349784][ T8020] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 82.350196][ T8020] CR2: 00007f96d80450b8 CR3: 000000004a16a000
CR4: 0000000000750ef0
[ 82.350717][ T8020] DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
[ 82.351243][ T8020] DR3: 0000000000000000 DR6: 00000000fffe0ff0
DR7: 0000000000000400
[ 82.351769][ T8020] PKRU: 55555554
[ 82.352011][ T8020] Kernel panic - not syncing: Fatal exception
[ 82.352665][ T8020] Kernel Offset: disabled
[ 82.352988][ T8020] Rebooting in 86400 seconds..
```
We have a C repro which can trigger this bug in latest upstream kernel
commit, listed below:
```
#define _GNU_SOURCE
#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
static unsigned long long procid;
static void sleep_ms(uint64_t ms)
{
usleep(ms * 1000);
}
static uint64_t current_time_ms(void)
{
struct timespec ts;
if (clock_gettime(CLOCK_MONOTONIC, &ts))
exit(1);
return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}
static bool write_file(const char* file, const char* what, ...)
{
char buf[1024];
va_list args;
va_start(args, what);
vsnprintf(buf, sizeof(buf), what, args);
va_end(args);
buf[sizeof(buf) - 1] = 0;
int len = strlen(buf);
int fd = open(file, O_WRONLY | O_CLOEXEC);
if (fd == -1)
return false;
if (write(fd, buf, len) != len) {
int err = errno;
close(fd);
errno = err;
return false;
}
close(fd);
return true;
}
static long syz_mod_dev(volatile long a0, volatile long a1, volatile long a2,
volatile long a3, volatile long a4)
{
int fd, sysfd;
char buf[1024], sysbuf[1024], input[1024];
char* hash;
char dev_num;
dev_num = 0;
strncpy(buf, (char*)a0, sizeof(buf) - 1);
buf[sizeof(buf) - 1] = 0;
while ((hash = strchr(buf, '#'))) {
*hash = '0' + (char)(a1 % 10);
a1 /= 10;
if (dev_num == 0)
dev_num = *hash;
}
fd = open(buf, a2, 0);
strncpy(sysbuf, (char*)a3, sizeof(sysbuf) - 1);
sysbuf[sizeof(sysbuf) - 1] = 0;
if ((hash = strchr(sysbuf, '#'))) {
*hash = dev_num;
while ((hash = strchr(sysbuf, '#'))) {
*hash = '0' + (char)(a1 % 10);
a1 /= 10;
}
}
sysfd = open(sysbuf, O_RDWR, 0);
strncpy(input, (char*)a4, sizeof(input) - 1);
input[sizeof(input) - 1] = 0;
hash = strchr(input, '\0');
sysfd = write(sysfd, input, hash - input + 1);
return fd;
}
static void kill_and_wait(int pid, int* status)
{
kill(-pid, SIGKILL);
kill(pid, SIGKILL);
for (int i = 0; i < 100; i++) {
if (waitpid(-1, status, WNOHANG | __WALL) == pid)
return;
usleep(1000);
}
DIR* dir = opendir("/sys/fs/fuse/connections");
if (dir) {
for (;;) {
struct dirent* ent = readdir(dir);
if (!ent)
break;
if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
continue;
char abort[300];
snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
ent->d_name);
int fd = open(abort, O_WRONLY);
if (fd == -1) {
continue;
}
if (write(fd, abort, 1) < 0) {
}
close(fd);
}
closedir(dir);
} else {
}
while (waitpid(-1, status, __WALL) != pid) {
}
}
static void setup_test()
{
prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
setpgrp();
write_file("/proc/self/oom_score_adj", "1000");
}
static void execute_one(void);
#define WAIT_FLAGS __WALL
static void loop(void)
{
int iter = 0;
for (;; iter++) {
int pid = fork();
if (pid < 0)
exit(1);
if (pid == 0) {
setup_test();
execute_one();
exit(0);
}
int status = 0;
uint64_t start = current_time_ms();
for (;;) {
if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
break;
sleep_ms(1);
if (current_time_ms() - start < 5000)
continue;
kill_and_wait(pid, &status);
break;
}
}
}
void execute_one(void)
{
memcpy((void*)0x20000000, "/dev/cpu/#/msr\000", 15);
memcpy((void*)0x200000c0, "/sys/devices/cpu/rdpmc\000", 23);
memcpy((void*)0x20000100, "0\000", 2);
syz_mod_dev(
/*dev=*/0x20000000, /*id=*/0x8001,
/*flags=O_TRUNC|O_PATH|O_NONBLOCK|O_NOATIME|O_EXCL|O_DIRECTORY|0x442*/
0x250ec2, /*file=*/0x200000c0, /*buf=*/0x20000100);
memcpy((void*)0x20000080, "/dev/cpu/#/msr\000", 15);
memcpy((void*)0x20000140, "/sys/devices/cpu/rdpmc\000", 23);
memcpy((void*)0x20000180, "1\000", 2);
syz_mod_dev(/*dev=*/0x20000080, /*id=*/0,
/*flags=__O_TMPFILE|O_APPEND*/ 0x400400, /*file=*/0x20000140,
/*buf=*/0x20000180);
}
int main(void)
{
syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul,
/*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1,
/*offset=*/0ul);
syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul,
/*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul,
/*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1,
/*offset=*/0ul);
syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul,
/*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1,
/*offset=*/0ul);
for (procid = 0; procid < 4; procid++) {
if (fork() == 0) {
loop();
}
}
sleep(1000000);
return 0;
}
```
If you have any questions, please contact us.
Reported by Yue Sun <samsun1006219@xxxxxxxxx>
Reported by xingwei lee <xrivendell7@xxxxxxxxx>
Best Regards,
Yue