Hi, when I tested io-uring on lts 5.15 I found this bug, do you think
this is a bug from io-uring or mm subsystem?
Syzkaller hit 'WARNING in get_pat_info' bug.
R10: 0000000004000053 R11: 0000000000000246 R12: 0000000000000004
R13: 00007fff4f16cfc8 R14: 00007f78cf8b04b0 R15: 0000000000000001
</TASK>
------------[ cut here ]------------
WARNING: CPU: 6 PID: 6779 at arch/x86/mm/pat/memtype.c:1020
get_pat_info+0x1a9/0x210 arch/x86/mm/pat/memtype.c:1020
Modules linked in:
CPU: 6 PID: 6779 Comm: syz-executor224 Not tainted 5.15.173-dirty #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
RIP: 0010:get_pat_info+0x1a9/0x210 arch/x86/mm/pat/memtype.c:1020
Code: ba 00 00 00 00 00 fc ff df 48 c1 e9 03 80 3c 11 00 75 64 49 89
5d 00 eb a6 90 0f 0b 90 e9 e2 fe ff ff b8 ea ff ff ff eb 96 90 <0f> 0b
90 b8 ea ff ff ff eb 8b 4c 89 f7 e8 f5 3e 7b 00 e9 b9 fe ff
RSP: 0018:ffffc900017df788 EFLAGS: 00010202
RAX: 0000000000000028 RBX: ffff88806d12fad0 RCX: 000ffffffffff000
RDX: 1ffff1100da25f64 RSI: 0000000020fff000 RDI: ffffc900017df618
RBP: ffffc900017df850 R08: 0000000000000000 R09: ffffc900017df710
R10: 0000000000000001 R11: 0000000000000001 R12: 1ffff920002fbef2
R13: 0000000000000000 R14: ffff88806d12fb20 R15: ffff88806d12fb70
FS: 000055555f38c480(0000) GS:ffff8880b9d80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000104 CR3: 000000001bf80000 CR4: 0000000000750ee0
PKRU: 55555554
Call Trace:
<TASK>
untrack_pfn+0xa4/0x1d0 arch/x86/mm/pat/memtype.c:1122
unmap_single_vma+0x14b/0x2d0 mm/memory.c:1600
zap_page_range_single+0x290/0x3d0 mm/memory.c:1704
remap_pfn_range_notrack+0x6f6/0x970 mm/memory.c:2464
remap_pfn_range+0xa5/0x110 mm/memory.c:2489
io_uring_mmap+0x330/0x430 io_uring/io_uring.c:9994
call_mmap include/linux/fs.h:2179 [inline]
mmap_region+0x9eb/0x12b0 mm/mmap.c:1791
do_mmap+0x635/0xe50 mm/mmap.c:1575
vm_mmap_pgoff+0x167/0x210 mm/util.c:551
ksys_mmap_pgoff+0x3b6/0x5f0 mm/mmap.c:1624
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x36/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x6c/0xd6
RIP: 0033:0x7f78cf8327dd
Code: 28 c3 e8 66 21 00 00 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:00007fff4f16ccf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f78cf8327dd
RDX: 0000000003000009 RSI: 0000000000001000 RDI: 0000000020fff000
RBP: 00007fff4f16cdb0 R08: 0000000000000003 R09: 0000000008000000
R10: 0000000004000053 R11: 0000000000000246 R12: 0000000000000004
R13: 00007fff4f16cfc8 R14: 00007f78cf8b04b0 R15: 0000000000000001
</TASK>
Syzkaller reproducer:
# {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1
Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false
NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false
KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false
Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false
HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false
FaultCall:0 FaultNth:0}}
r0 = io_uring_setup(0x9b0, &(0x7f0000000100)={0x0, 0xa91a, 0x40, 0x0, 0x33c})
mmap$IORING_OFF_CQ_RING(&(0x7f0000fff000/0x1000)=nil, 0x1000,
0x3000009, 0x4000053, r0, 0x8000000) (fail_nth: 4)
C reproducer:
// autogenerated by syzkaller (https://github.com/google/syzkaller)
#define _GNU_SOURCE
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.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>
#ifndef __NR_io_uring_setup
#define __NR_io_uring_setup 425
#endif
static __thread int clone_ongoing;
static __thread int skip_segv;
static __thread jmp_buf segv_env;
static void segv_handler(int sig, siginfo_t* info, void* ctx)
{
if (__atomic_load_n(&clone_ongoing, __ATOMIC_RELAXED) != 0) {
exit(sig);
}
uintptr_t addr = (uintptr_t)info->si_addr;
const uintptr_t prog_start = 1 << 20;
const uintptr_t prog_end = 100 << 20;
int skip = __atomic_load_n(&skip_segv, __ATOMIC_RELAXED) != 0;
int valid = addr < prog_start || addr > prog_end;
if (skip && valid) {
_longjmp(segv_env, 1);
}
exit(sig);
}
static void install_segv_handler(void)
{
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = SIG_IGN;
syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8);
syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8);
memset(&sa, 0, sizeof(sa));
sa.sa_sigaction = segv_handler;
sa.sa_flags = SA_NODEFER | SA_SIGINFO;
sigaction(SIGSEGV, &sa, NULL);
sigaction(SIGBUS, &sa, NULL);
}
#define NONFAILING(...) \
({ \
int ok = 1; \
__atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \
if (_setjmp(segv_env) == 0) { \
__VA_ARGS__; \
} else \
ok = 0; \
__atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \
ok; \
})
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 const char* setup_fault()
{
int fd = open("/proc/self/make-it-fail", O_WRONLY);
if (fd == -1)
return "CONFIG_FAULT_INJECTION is not enabled";
close(fd);
fd = open("/proc/thread-self/fail-nth", O_WRONLY);
if (fd == -1)
return "kernel does not have systematic fault injection support";
close(fd);
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)
return "failed to write fault injection file";
}
}
return NULL;
}
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);
const char* reason;
(void)reason;
if ((reason = setup_fault()))
printf("the reproducer may not work as expected: fault injection setup "
"failed: %s\n",
reason);
install_segv_handler();
intptr_t res = 0;
if (write(1, "executing program\n", sizeof("executing program\n") - 1)) {
}
NONFAILING(*(uint32_t*)0x20000104 = 0xa91a);
NONFAILING(*(uint32_t*)0x20000108 = 0x40);
NONFAILING(*(uint32_t*)0x2000010c = 0);
NONFAILING(*(uint32_t*)0x20000110 = 0x33c);
NONFAILING(*(uint32_t*)0x20000118 = -1);
NONFAILING(memset((void*)0x2000011c, 0, 12));
res =
syscall(__NR_io_uring_setup, /*entries=*/0x9b0, /*params=*/0x20000100ul);
if (res != -1)
r[0] = res;
inject_fault(4);
syscall(__NR_mmap, /*addr=*/0x20fff000ul, /*len=*/0x1000ul,
/*prot=PROT_GROWSUP|PROT_GROWSDOWN|PROT_SEM|PROT_READ*/ 0x3000009ul,
/*flags=MAP_SHARED_VALIDATE|MAP_UNINITIALIZED|MAP_FIXED|MAP_32BIT*/
0x4000053ul, /*fd=*/r[0], /*offset=*/0x8000000ul);
return 0;
}
