Hi, We would like to report the following bug which has been found by our modified version of syzkaller. ====================================================== description: KMSAN: uninit-value in sr_check_events affected file: drivers/scsi/sr.c kernel version: 6.2.0-rc5 kernel commit: 41c66f47061608dc1fd493eebce198f0e74cc2d7 git tree: kmsan kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=a9a22da1efde3af6 crash reproducer: attached ====================================================== Crash log: ====================================================== BUG: KMSAN: uninit-value in sr_check_events+0x12d2/0x13c0 drivers/scsi/sr.c:269 sr_check_events+0x12d2/0x13c0 drivers/scsi/sr.c:269 cdrom_update_events drivers/cdrom/cdrom.c:1485 [inline] cdrom_check_events+0x61/0x170 drivers/cdrom/cdrom.c:1495 sr_block_check_events+0xf5/0x130 drivers/scsi/sr.c:559 disk_check_events+0xf1/0x950 block/disk-events.c:193 disk_clear_events block/disk-events.c:248 [inline] bdev_check_media_change+0x26a/0x7f0 block/disk-events.c:279 sr_block_open+0x159/0x340 drivers/scsi/sr.c:494 blkdev_get_whole+0xb4/0x700 block/bdev.c:672 blkdev_get_by_dev+0x4c9/0x1280 block/bdev.c:822 blkdev_open+0x216/0x440 block/fops.c:478 do_dentry_open+0xf85/0x1970 fs/open.c:882 vfs_open+0x75/0xa0 fs/open.c:1013 do_open fs/namei.c:3557 [inline] path_openat+0x4c4b/0x5a00 fs/namei.c:3714 do_filp_open+0x252/0x660 fs/namei.c:3741 do_sys_openat2+0x200/0x920 fs/open.c:1310 do_sys_open fs/open.c:1326 [inline] __do_sys_openat fs/open.c:1342 [inline] __se_sys_openat fs/open.c:1337 [inline] __x64_sys_openat+0x285/0x310 fs/open.c:1337 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Uninit was stored to memory at: sr_check_events+0xb04/0x13c0 drivers/scsi/sr.c:216 cdrom_update_events drivers/cdrom/cdrom.c:1485 [inline] cdrom_check_events+0x61/0x170 drivers/cdrom/cdrom.c:1495 sr_block_check_events+0xf5/0x130 drivers/scsi/sr.c:559 disk_check_events+0xf1/0x950 block/disk-events.c:193 disk_clear_events block/disk-events.c:248 [inline] bdev_check_media_change+0x26a/0x7f0 block/disk-events.c:279 sr_block_open+0x159/0x340 drivers/scsi/sr.c:494 blkdev_get_whole+0xb4/0x700 block/bdev.c:672 blkdev_get_by_dev+0x4c9/0x1280 block/bdev.c:822 blkdev_open+0x216/0x440 block/fops.c:478 do_dentry_open+0xf85/0x1970 fs/open.c:882 vfs_open+0x75/0xa0 fs/open.c:1013 do_open fs/namei.c:3557 [inline] path_openat+0x4c4b/0x5a00 fs/namei.c:3714 do_filp_open+0x252/0x660 fs/namei.c:3741 do_sys_openat2+0x200/0x920 fs/open.c:1310 do_sys_open fs/open.c:1326 [inline] __do_sys_openat fs/open.c:1342 [inline] __se_sys_openat fs/open.c:1337 [inline] __x64_sys_openat+0x285/0x310 fs/open.c:1337 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Local variable sshdr.i created at: sr_get_events drivers/scsi/sr.c:172 [inline] sr_check_events+0x11f/0x13c0 drivers/scsi/sr.c:215 cdrom_update_events drivers/cdrom/cdrom.c:1485 [inline] cdrom_check_events+0x61/0x170 drivers/cdrom/cdrom.c:1495 CPU: 0 PID: 22994 Comm: syz-executor.1 Not tainted 6.2.0-rc5-00010-g41c66f470616 #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 -- Thanks and Regards, Dipanjan
Attachment:
repro.syz
Description: Binary data
// autogenerated by syzkaller (https://github.com/google/syzkaller) #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 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 int inject_fault(int nth) { int fd; fd = open("/proc/thread-self/fail-nth", O_RDWR); if (fd == -1) exit(1); char buf[16]; sprintf(buf, "%d", nth); if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf)) exit(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 setup_fault() { static struct { const char* file; const char* val; bool fatal; } files[] = { {"/sys/kernel/debug/failslab/ignore-gfp-wait", "N", true}, {"/sys/kernel/debug/fail_futex/ignore-private", "N", false}, {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem", "N", false}, {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-wait", "N", false}, {"/sys/kernel/debug/fail_page_alloc/min-order", "0", false}, }; unsigned i; for (i = 0; i < sizeof(files) / sizeof(files[0]); i++) { if (!write_file(files[i].file, files[i].val)) { if (files[i].fatal) exit(1); } } } 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*)0x20000040, "/dev/sr0\000", 9); inject_fault(7); syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000040ul, 0x48800ul, 0ul); } int main(void) { syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); setup_fault(); loop(); return 0; }
