Messages in this thread | | | From | Dipanjan Das <> | Date | Sun, 12 Feb 2023 09:00:17 -0800 | Subject | BUG: unable to handle kernel paging request in n_tty_open |
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Hi,
We would like to report the following bug which has been found by our modified version of syzkaller.
====================================================== description: BUG: unable to handle kernel paging request in n_tty_open affected file: drivers/tty/tty_ldisc.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: ====================================================== RBP: 00007f7117670c30 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000d R13: 00007f71165abf6c R14: 00007f71165abf60 R15: 00007f7117670d80 </TASK> BUG: unable to handle page fault for address: ffffd10016bfa050 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 11410067 P4D 11410067 PUD 1157d067 PMD 31910067 PTE 0 Oops: 0002 [#1] PREEMPT SMP CPU: 1 PID: 14496 Comm: syz-executor.4 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 RIP: 0010:n_tty_open+0xa5/0x240 drivers/tty/n_tty.c:1883 Code: c8 48 c7 c7 c0 79 c0 8f e8 f8 0e ef fb 4d 8d 67 50 48 8b 18 8b 02 89 45 d0 4d 85 ed 0f 85 12 01 00 00 4c 89 e7 e8 0b 0f ef fb <48> 89 18 48 85 db 0f 85 0b 01 00 00 4d 8d a7 88 22 00 00 48 8b 45 RSP: 0018:ffff8880a72036a0 EFLAGS: 00010286 RAX: ffffd10016bfa050 RBX: 0000000000000000 RCX: ffffd10016bfa050 RDX: ffffd90016bfa050 RSI: 0000000000000001 RDI: ffffc90016bfa050 RBP: ffff8880a72036e0 R08: 0000000000000001 R09: ffff8880a6a03458 R10: 0000000000000001 R11: 0000000000000000 R12: ffffc90016bfa050 R13: 0000000000000000 R14: ffff88808b6c1000 R15: ffffc90016bfa000 FS: 00007f7117671700(0000) GS:ffff88813fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffd10016bfa050 CR3: 00000000a7110000 CR4: 0000000000150ee0 Call Trace: <TASK> tty_ldisc_open drivers/tty/tty_ldisc.c:433 [inline] tty_ldisc_setup+0xfc/0x4c0 drivers/tty/tty_ldisc.c:740 tty_init_dev+0x4b0/0xad0 drivers/tty/tty_io.c:1437 tty_open_by_driver drivers/tty/tty_io.c:2079 [inline] tty_open+0x176f/0x20b0 drivers/tty/tty_io.c:2126 chrdev_open+0xa45/0xb80 fs/char_dev.c:414 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 RIP: 0033:0x7f711648d59d Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7117670bd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f71165abf60 RCX: 00007f711648d59d RDX: 00000000000a6503 RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 00007f7117670c30 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000d R13: 00007f71165abf6c R14: 00007f71165abf60 R15: 00007f7117670d80 </TASK> Modules linked in: CR2: ffffd10016bfa050 ---[ end trace 0000000000000000 ]--- RIP: 0010:n_tty_open+0xa5/0x240 drivers/tty/n_tty.c:1883 Code: c8 48 c7 c7 c0 79 c0 8f e8 f8 0e ef fb 4d 8d 67 50 48 8b 18 8b 02 89 45 d0 4d 85 ed 0f 85 12 01 00 00 4c 89 e7 e8 0b 0f ef fb <48> 89 18 48 85 db 0f 85 0b 01 00 00 4d 8d a7 88 22 00 00 48 8b 45 RSP: 0018:ffff8880a72036a0 EFLAGS: 00010286 RAX: ffffd10016bfa050 RBX: 0000000000000000 RCX: ffffd10016bfa050 RDX: ffffd90016bfa050 RSI: 0000000000000001 RDI: ffffc90016bfa050 RBP: ffff8880a72036e0 R08: 0000000000000001 R09: ffff8880a6a03458 R10: 0000000000000001 R11: 0000000000000000 R12: ffffc90016bfa050 R13: 0000000000000000 R14: ffff88808b6c1000 R15: ffffc90016bfa000 FS: 00007f7117671700(0000) GS:ffff88813fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffd10016bfa050 CR3: 00000000a7110000 CR4: 0000000000150ee0 ---------------- Code disassembly (best guess): 0: c8 48 c7 c7 enterq $0xc748,$0xc7 4: c0 79 c0 8f sarb $0x8f,-0x40(%rcx) 8: e8 f8 0e ef fb callq 0xfbef0f05 d: 4d 8d 67 50 lea 0x50(%r15),%r12 11: 48 8b 18 mov (%rax),%rbx 14: 8b 02 mov (%rdx),%eax 16: 89 45 d0 mov %eax,-0x30(%rbp) 19: 4d 85 ed test %r13,%r13 1c: 0f 85 12 01 00 00 jne 0x134 22: 4c 89 e7 mov %r12,%rdi 25: e8 0b 0f ef fb callq 0xfbef0f35 * 2a: 48 89 18 mov %rbx,(%rax) <-- trapping instruction 2d: 48 85 db test %rbx,%rbx 30: 0f 85 0b 01 00 00 jne 0x141 36: 4d 8d a7 88 22 00 00 lea 0x2288(%r15),%r12 3d: 48 rex.W 3e: 8b .byte 0x8b 3f: 45 rex.RB
-- Thanks and Regards,
Dipanjan // 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*)0x20000000, "/dev/ttyS3\000", 11); inject_fault(13); syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000000ul, 0xa6503ul, 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; } [unhandled content-type:application/octet-stream] | |