Messages in this thread | | | From | Sam Sun <> | Date | Tue, 23 Apr 2024 18:10:38 +0800 | Subject | [Linux kernel bug] divide error in wq_update_node_max_active |
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Dear developers and maintainers,
We encountered a divide error bug while using our modified syzkaller. It was tested against the latest upstream kernel (6.9-rc5). The kernel was compiled by clang 14.0.0, and kernel config and C repro are attached to this email. Kernel crash log is listed below. ```
divide error: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 1 PID: 21 Comm: cpuhp/1 Not tainted 6.9.0-rc5 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:wq_update_node_max_active+0x369/0x6b0 kernel/workqueue.c:1605 Code: 24 bf 00 00 00 80 44 89 fe e8 83 27 33 00 41 83 fc ff 75 0d 41 81 ff 00 00 00 80 0f 84 68 01 00 00 e8 fb 22 33 00 44 89 f8 99 <41> f7 fc 89 c5 89 c7 44 89 ee e8 a8 24 33 00 89 ef 8b 5c 24 04 89 RSP: 0018:ffffc9000018fbb0 EFLAGS: 00010293 RAX: 00000000000000ff RBX: 0000000000000001 RCX: ffff888100ada500 RDX: 0000000000000000 RSI: 00000000000000ff RDI: 0000000080000000 RBP: 0000000000000001 R08: ffffffff815b1fcd R09: 1ffff1100364ad72 R10: dffffc0000000000 R11: ffffed100364ad73 R12: 0000000000000000 R13: 0000000000000100 R14: 0000000000000000 R15: 00000000000000ff FS: 0000000000000000(0000) GS:ffff888135c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb8c06ca6f8 CR3: 000000010d6c6000 CR4: 0000000000750ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> workqueue_offline_cpu+0x56f/0x600 kernel/workqueue.c:6525 cpuhp_invoke_callback+0x4e1/0x870 kernel/cpu.c:194 cpuhp_thread_fun+0x411/0x7d0 kernel/cpu.c:1092 smpboot_thread_fn+0x544/0xa10 kernel/smpboot.c:164 kthread+0x2ed/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:wq_update_node_max_active+0x369/0x6b0 kernel/workqueue.c:1605 Code: 24 bf 00 00 00 80 44 89 fe e8 83 27 33 00 41 83 fc ff 75 0d 41 81 ff 00 00 00 80 0f 84 68 01 00 00 e8 fb 22 33 00 44 89 f8 99 <41> f7 fc 89 c5 89 c7 44 89 ee e8 a8 24 33 00 89 ef 8b 5c 24 04 89 RSP: 0018:ffffc9000018fbb0 EFLAGS: 00010293 RAX: 00000000000000ff RBX: 0000000000000001 RCX: ffff888100ada500 RDX: 0000000000000000 RSI: 00000000000000ff RDI: 0000000080000000 RBP: 0000000000000001 R08: ffffffff815b1fcd R09: 1ffff1100364ad72 R10: dffffc0000000000 R11: ffffed100364ad73 R12: 0000000000000000 R13: 0000000000000100 R14: 0000000000000000 R15: 00000000000000ff FS: 0000000000000000(0000) GS:ffff888135c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb8c06ca6f8 CR3: 000000010d6c6000 CR4: 0000000000750ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 ---------------- Code disassembly (best guess): 0: 24 bf and $0xbf,%al 2: 00 00 add %al,(%rax) 4: 00 80 44 89 fe e8 add %al,-0x170176bc(%rax) a: 83 27 33 andl $0x33,(%rdi) d: 00 41 83 add %al,-0x7d(%rcx) 10: fc cld 11: ff 75 0d push 0xd(%rbp) 14: 41 81 ff 00 00 00 80 cmp $0x80000000,%r15d 1b: 0f 84 68 01 00 00 je 0x189 21: e8 fb 22 33 00 call 0x332321 26: 44 89 f8 mov %r15d,%eax 29: 99 cltd * 2a: 41 f7 fc idiv %r12d <-- trapping instruction 2d: 89 c5 mov %eax,%ebp 2f: 89 c7 mov %eax,%edi 31: 44 89 ee mov %r13d,%esi 34: e8 a8 24 33 00 call 0x3324e1 39: 89 ef mov %ebp,%edi 3b: 8b 5c 24 04 mov 0x4(%rsp),%ebx 3f: 89 .byte 0x89 ``` If you have any questions, please contact us.
Reported by Yue Sun <samsun1006219@gmail.com> Reported by xingwei lee <xrivendell7@gmail.com>
Best Regards, Yue [unhandled content-type:application/octet-stream]#define _GNU_SOURCE
#include <endian.h> #include <fcntl.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/stat.h> #include <sys/syscall.h> #include <sys/types.h> #include <unistd.h>
static long syz_mod_dev(volatile long a0, volatile long a1, volatile long a2, volatile long a3, volatile long a4, volatile long a5) { 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; }
uint64_t r[1] = {0xffffffffffffffff};
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); intptr_t res = 0; memcpy((void*)0x20000340, "/dev/nvme-fabrics\000", 18); memcpy((void*)0x20000380, "/sys/devices/virtual/workqueue/nvme-delete-wq/cpumask\000", 54); memcpy((void*)0x200003c0, "2\000", 2); syz_mod_dev(/*dev=*/0x20000340, /*id=*/0, /*flags=*/0, /*file=*/0x20000380, /*buf=*/0x200003c0, /*fd=*/-1); memcpy((void*)0x20000040, "/sys/devices/system/cpu/cpu1/online\000", 36); res = syscall(__NR_openat, /*fd=*/0xffffffffffffff9cul, /*file=*/0x20000040ul, /*flags=*/2ul, /*mode=*/0ul); if (res != -1) r[0] = res; sprintf((char*)0x20002780, "%020llu", (long long)0); *(uint8_t*)0x20002794 = 0; syscall(__NR_write, /*fd=*/r[0], /*buf=*/0x20002780ul, /*len=*/0x15ul); return 0; }
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