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Date: Sun, 9 Jun 2024 09:04:31 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Sam Sun <samsun1006219@...il.com>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org,
syzkaller-bugs@...glegroups.com, peterz@...radead.org, jpoimboe@...nel.org,
jbaron@...mai.com, ardb@...nel.org, tglx@...utronix.de, mingo@...hat.com,
Borislav Petkov <bp@...en8.de>, dave.hansen@...ux.intel.com, hpa@...or.com,
xrivendell7@...il.com, Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Tejun Heo <tj@...nel.org>
Subject: Re: [Linux kernel bug] WARNING in static_key_slow_inc_cpuslocked
On Sun, 9 Jun 2024 14:33:01 +0800
Sam Sun <samsun1006219@...il.com> wrote:
> 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!
This is not a bug with jump labels. It's a bug with whatever is using jump
labels. Looks like something tried to modify a jump label that no longer
exists.
> [ 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
So, something in kernfs modified a jump label location that was freed?
-- Steve
> [ 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@...il.com>
> Reported by xingwei lee <xrivendell7@...il.com>
>
> Best Regards,
> Yue
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