From: Jens Axboe <axboe@kernel.dk>
To: Dominique Martinet <asmadeus@codewreck.org>
Cc: Christian Schoenebeck <linux_oss@crudebyte.com>,
Eric Van Hensbergen <ericvh@kernel.org>,
netdev <netdev@vger.kernel.org>, Jakub Kicinski <kuba@kernel.org>,
Pengfei Xu <pengfei.xu@intel.com>,
v9fs-developer@lists.sourceforge.net
Subject: Re: [PATCH v2] 9p/client: don't assume signal_pending() clears on recalc_sigpending()
Date: Mon, 6 Feb 2023 14:56:57 -0700 [thread overview]
Message-ID: <00a0809e-7b47-c43c-3a13-a84cd692f514@kernel.dk> (raw)
In-Reply-To: <Y+F0KrAmOuoJcVt/@codewreck.org>
[-- Attachment #1: Type: text/plain, Size: 3531 bytes --]
On 2/6/23 2:42?PM, Dominique Martinet wrote:
> Jens Axboe wrote on Mon, Feb 06, 2023 at 01:19:24PM -0700:
>>> I agree with your assessment that we can't use task_work_run(), I assume
>>> it's also quite bad to just clear the flag?
>>> I'm not familiar with these task at all, in which case do they happen?
>>> Would you be able to share an easy reproducer so that I/someone can try
>>> on various transports?
>>
>> You can't just clear the flag without also running the task_work. Hence
>> it either needs to be done right there, or leave it pending and let the
>> exit to userspace take care of it.
>
> Sorry I didn't develop that idea; the signal path resets the pending
> signal when we're done, I assumed we could also reset the TWA_SIGNAL
> flag when we're done flushing. That might take a while though, so it's
> far from optimal.
Sure, if you set it again when done, then it will probably work just
fine. But you need to treat TIF_NOTIFY_SIGNAL and TIF_SIGPENDING
separately. An attempt at that at the end of this email, totally
untested, and I'm not certain it's a good idea at all (see below). Is
there a reason why we can't exit and get the task_work processed
instead? That'd be greatly preferable.
>>> If it's "rare enough" I'd say sacrificing the connection might make more
>>> sense than a busy loop, but if it's becoming common I think we'll need
>>> to spend some more time thinking about it...
>>> It might be less effort to dig out my async flush commits if this become
>>> too complicated, but I wish I could say I have time for it...
>>
>> It can be a number of different things - eg fput() will do it.
>
> Hm, schedule_delayed_work on the last fput, ok.
> I was wondering what it had to do with the current 9p thread, but since
> it's not scheduled on a particular cpu it can pick another cpu to wake
> up, that makes sense -- although conceptually it feels rather bad to
> interrupt a remote IO because of a local task that can be done later;
> e.g. between having the fput wait a bit, or cancel a slow operation like
> a 1MB write, I'd rather make the fput wait.
> Do you know why that signal/interrupt is needed in the first place?
It's needed if the task is currently sleeping in the kernel, to abort a
sleeping loop. The task_work may contain actions that will result in the
sleep loop being satisfied and hence ending, which means it needs to be
processed. That's my worry with the check-and-clear, then reset state
solution.
>> The particular case that I came across was io_uring, which will use
>> TWA_SIGNAL based task_work for retry operations (and other things). If
>> you use io_uring, and depending on how you setup the ring, it can be
>> quite common or will never happen. Dropping the connection task_work
>> being pending is not a viable solution, I'm afraid.
>
> Thanks for confirming that it's perfectly normal, let's not drop
> connections :)
>
> My preferred approach is still to try and restore the async flush code,
> but that will take a while -- it's not something that'll work right away
> and I want some tests so it won't be ready for this merge window.
> If we can have some sort of workaround until then it'll probably be for
> the best, but I don't have any other idea (than temporarily clearing the
> flag) at this point.
>
> I'll setup some uring IO on 9p and see if I can produce these.
I'm attaching a test case. I don't think it's particularly useful, but
it does nicely demonstrate the infinite loop that 9p gets into if
there's task_work pending.
--
Jens Axboe
[-- Attachment #2: repro.c --]
[-- Type: text/x-csrc, Size: 19895 bytes --]
// autogenerated by syzkaller (https://github.com/google/syzkaller)
#define _GNU_SOURCE
#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/mount.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>
#include <linux/loop.h>
#ifndef __NR_io_uring_setup
#define __NR_io_uring_setup 425
#endif
#ifndef __NR_memfd_create
#define __NR_memfd_create 319
#endif
static unsigned long long procid;
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 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;
}
//% This code is derived from puff.{c,h}, found in the zlib development. The
//% original files come with the following copyright notice:
//% Copyright (C) 2002-2013 Mark Adler, all rights reserved
//% version 2.3, 21 Jan 2013
//% This software is provided 'as-is', without any express or implied
//% warranty. In no event will the author be held liable for any damages
//% arising from the use of this software.
//% Permission is granted to anyone to use this software for any purpose,
//% including commercial applications, and to alter it and redistribute it
//% freely, subject to the following restrictions:
//% 1. The origin of this software must not be misrepresented; you must not
//% claim that you wrote the original software. If you use this software
//% in a product, an acknowledgment in the product documentation would be
//% appreciated but is not required.
//% 2. Altered source versions must be plainly marked as such, and must not be
//% misrepresented as being the original software.
//% 3. This notice may not be removed or altered from any source distribution.
//% Mark Adler madler@alumni.caltech.edu
//% BEGIN CODE DERIVED FROM puff.{c,h}
#define MAXBITS 15
#define MAXLCODES 286
#define MAXDCODES 30
#define MAXCODES (MAXLCODES + MAXDCODES)
#define FIXLCODES 288
struct puff_state {
unsigned char* out;
unsigned long outlen;
unsigned long outcnt;
const unsigned char* in;
unsigned long inlen;
unsigned long incnt;
int bitbuf;
int bitcnt;
jmp_buf env;
};
static int puff_bits(struct puff_state* s, int need)
{
long val = s->bitbuf;
while (s->bitcnt < need) {
if (s->incnt == s->inlen)
longjmp(s->env, 1);
val |= (long)(s->in[s->incnt++]) << s->bitcnt;
s->bitcnt += 8;
}
s->bitbuf = (int)(val >> need);
s->bitcnt -= need;
return (int)(val & ((1L << need) - 1));
}
static int puff_stored(struct puff_state* s)
{
s->bitbuf = 0;
s->bitcnt = 0;
if (s->incnt + 4 > s->inlen)
return 2;
unsigned len = s->in[s->incnt++];
len |= s->in[s->incnt++] << 8;
if (s->in[s->incnt++] != (~len & 0xff) ||
s->in[s->incnt++] != ((~len >> 8) & 0xff))
return -2;
if (s->incnt + len > s->inlen)
return 2;
if (s->outcnt + len > s->outlen)
return 1;
for (; len--; s->outcnt++, s->incnt++) {
if (s->in[s->incnt])
s->out[s->outcnt] = s->in[s->incnt];
}
return 0;
}
struct puff_huffman {
short* count;
short* symbol;
};
static int puff_decode(struct puff_state* s, const struct puff_huffman* h)
{
int first = 0;
int index = 0;
int bitbuf = s->bitbuf;
int left = s->bitcnt;
int code = first = index = 0;
int len = 1;
short* next = h->count + 1;
while (1) {
while (left--) {
code |= bitbuf & 1;
bitbuf >>= 1;
int count = *next++;
if (code - count < first) {
s->bitbuf = bitbuf;
s->bitcnt = (s->bitcnt - len) & 7;
return h->symbol[index + (code - first)];
}
index += count;
first += count;
first <<= 1;
code <<= 1;
len++;
}
left = (MAXBITS + 1) - len;
if (left == 0)
break;
if (s->incnt == s->inlen)
longjmp(s->env, 1);
bitbuf = s->in[s->incnt++];
if (left > 8)
left = 8;
}
return -10;
}
static int puff_construct(struct puff_huffman* h, const short* length, int n)
{
int len;
for (len = 0; len <= MAXBITS; len++)
h->count[len] = 0;
int symbol;
for (symbol = 0; symbol < n; symbol++)
(h->count[length[symbol]])++;
if (h->count[0] == n)
return 0;
int left = 1;
for (len = 1; len <= MAXBITS; len++) {
left <<= 1;
left -= h->count[len];
if (left < 0)
return left;
}
short offs[MAXBITS + 1];
offs[1] = 0;
for (len = 1; len < MAXBITS; len++)
offs[len + 1] = offs[len] + h->count[len];
for (symbol = 0; symbol < n; symbol++)
if (length[symbol] != 0)
h->symbol[offs[length[symbol]]++] = symbol;
return left;
}
static int puff_codes(struct puff_state* s, const struct puff_huffman* lencode,
const struct puff_huffman* distcode)
{
static const short lens[29] = {3, 4, 5, 6, 7, 8, 9, 10, 11, 13,
15, 17, 19, 23, 27, 31, 35, 43, 51, 59,
67, 83, 99, 115, 131, 163, 195, 227, 258};
static const short lext[29] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2,
2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0};
static const short dists[30] = {
1, 2, 3, 4, 5, 7, 9, 13, 17, 25,
33, 49, 65, 97, 129, 193, 257, 385, 513, 769,
1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577};
static const short dext[30] = {0, 0, 0, 0, 1, 1, 2, 2, 3, 3,
4, 4, 5, 5, 6, 6, 7, 7, 8, 8,
9, 9, 10, 10, 11, 11, 12, 12, 13, 13};
int symbol;
do {
symbol = puff_decode(s, lencode);
if (symbol < 0)
return symbol;
if (symbol < 256) {
if (s->outcnt == s->outlen)
return 1;
if (symbol)
s->out[s->outcnt] = symbol;
s->outcnt++;
} else if (symbol > 256) {
symbol -= 257;
if (symbol >= 29)
return -10;
int len = lens[symbol] + puff_bits(s, lext[symbol]);
symbol = puff_decode(s, distcode);
if (symbol < 0)
return symbol;
unsigned dist = dists[symbol] + puff_bits(s, dext[symbol]);
if (dist > s->outcnt)
return -11;
if (s->outcnt + len > s->outlen)
return 1;
while (len--) {
if (dist <= s->outcnt && s->out[s->outcnt - dist])
s->out[s->outcnt] = s->out[s->outcnt - dist];
s->outcnt++;
}
}
} while (symbol != 256);
return 0;
}
static int puff_fixed(struct puff_state* s)
{
static int virgin = 1;
static short lencnt[MAXBITS + 1], lensym[FIXLCODES];
static short distcnt[MAXBITS + 1], distsym[MAXDCODES];
static struct puff_huffman lencode, distcode;
if (virgin) {
lencode.count = lencnt;
lencode.symbol = lensym;
distcode.count = distcnt;
distcode.symbol = distsym;
short lengths[FIXLCODES];
int symbol;
for (symbol = 0; symbol < 144; symbol++)
lengths[symbol] = 8;
for (; symbol < 256; symbol++)
lengths[symbol] = 9;
for (; symbol < 280; symbol++)
lengths[symbol] = 7;
for (; symbol < FIXLCODES; symbol++)
lengths[symbol] = 8;
puff_construct(&lencode, lengths, FIXLCODES);
for (symbol = 0; symbol < MAXDCODES; symbol++)
lengths[symbol] = 5;
puff_construct(&distcode, lengths, MAXDCODES);
virgin = 0;
}
return puff_codes(s, &lencode, &distcode);
}
static int puff_dynamic(struct puff_state* s)
{
static const short order[19] = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5,
11, 4, 12, 3, 13, 2, 14, 1, 15};
int nlen = puff_bits(s, 5) + 257;
int ndist = puff_bits(s, 5) + 1;
int ncode = puff_bits(s, 4) + 4;
if (nlen > MAXLCODES || ndist > MAXDCODES)
return -3;
short lengths[MAXCODES];
int index;
for (index = 0; index < ncode; index++)
lengths[order[index]] = puff_bits(s, 3);
for (; index < 19; index++)
lengths[order[index]] = 0;
short lencnt[MAXBITS + 1], lensym[MAXLCODES];
struct puff_huffman lencode = {lencnt, lensym};
int err = puff_construct(&lencode, lengths, 19);
if (err != 0)
return -4;
index = 0;
while (index < nlen + ndist) {
int symbol;
int len;
symbol = puff_decode(s, &lencode);
if (symbol < 0)
return symbol;
if (symbol < 16)
lengths[index++] = symbol;
else {
len = 0;
if (symbol == 16) {
if (index == 0)
return -5;
len = lengths[index - 1];
symbol = 3 + puff_bits(s, 2);
} else if (symbol == 17)
symbol = 3 + puff_bits(s, 3);
else
symbol = 11 + puff_bits(s, 7);
if (index + symbol > nlen + ndist)
return -6;
while (symbol--)
lengths[index++] = len;
}
}
if (lengths[256] == 0)
return -9;
err = puff_construct(&lencode, lengths, nlen);
if (err && (err < 0 || nlen != lencode.count[0] + lencode.count[1]))
return -7;
short distcnt[MAXBITS + 1], distsym[MAXDCODES];
struct puff_huffman distcode = {distcnt, distsym};
err = puff_construct(&distcode, lengths + nlen, ndist);
if (err && (err < 0 || ndist != distcode.count[0] + distcode.count[1]))
return -8;
return puff_codes(s, &lencode, &distcode);
}
static int puff(unsigned char* dest, unsigned long* destlen,
const unsigned char* source, unsigned long sourcelen)
{
struct puff_state s = {
.out = dest,
.outlen = *destlen,
.outcnt = 0,
.in = source,
.inlen = sourcelen,
.incnt = 0,
.bitbuf = 0,
.bitcnt = 0,
};
int err;
if (setjmp(s.env) != 0)
err = 2;
else {
int last;
do {
last = puff_bits(&s, 1);
int type = puff_bits(&s, 2);
err = type == 0 ? puff_stored(&s)
: (type == 1 ? puff_fixed(&s)
: (type == 2 ? puff_dynamic(&s) : -1));
if (err != 0)
break;
} while (!last);
}
*destlen = s.outcnt;
return err;
}
//% END CODE DERIVED FROM puff.{c,h}
#define ZLIB_HEADER_WIDTH 2
static int puff_zlib_to_file(const unsigned char* source,
unsigned long sourcelen, int dest_fd)
{
if (sourcelen < ZLIB_HEADER_WIDTH)
return 0;
source += ZLIB_HEADER_WIDTH;
sourcelen -= ZLIB_HEADER_WIDTH;
const unsigned long max_destlen = 132 << 20;
void* ret = mmap(0, max_destlen, PROT_WRITE | PROT_READ,
MAP_PRIVATE | MAP_ANON, -1, 0);
if (ret == MAP_FAILED)
return -1;
unsigned char* dest = (unsigned char*)ret;
unsigned long destlen = max_destlen;
int err = puff(dest, &destlen, source, sourcelen);
if (err) {
munmap(dest, max_destlen);
errno = -err;
return -1;
}
if (write(dest_fd, dest, destlen) != (ssize_t)destlen) {
munmap(dest, max_destlen);
return -1;
}
return munmap(dest, destlen);
}
static int setup_loop_device(unsigned char* data, unsigned long size,
const char* loopname, int* loopfd_p)
{
int err = 0, loopfd = -1;
int memfd = syscall(__NR_memfd_create, "syzkaller", 0);
if (memfd == -1) {
err = errno;
goto error;
}
if (puff_zlib_to_file(data, size, memfd)) {
err = errno;
goto error_close_memfd;
}
loopfd = open(loopname, O_RDWR);
if (loopfd == -1) {
err = errno;
goto error_close_memfd;
}
if (ioctl(loopfd, LOOP_SET_FD, memfd)) {
if (errno != EBUSY) {
err = errno;
goto error_close_loop;
}
ioctl(loopfd, LOOP_CLR_FD, 0);
usleep(1000);
if (ioctl(loopfd, LOOP_SET_FD, memfd)) {
err = errno;
goto error_close_loop;
}
}
close(memfd);
*loopfd_p = loopfd;
return 0;
error_close_loop:
close(loopfd);
error_close_memfd:
close(memfd);
error:
errno = err;
return -1;
}
static long syz_mount_image(volatile long fsarg, volatile long dir,
volatile long flags, volatile long optsarg,
volatile long change_dir,
volatile unsigned long size, volatile long image)
{
unsigned char* data = (unsigned char*)image;
int res = -1, err = 0, loopfd = -1, need_loop_device = !!size;
char* mount_opts = (char*)optsarg;
char* target = (char*)dir;
char* fs = (char*)fsarg;
char* source = NULL;
char loopname[64];
if (need_loop_device) {
memset(loopname, 0, sizeof(loopname));
snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid);
if (setup_loop_device(data, size, loopname, &loopfd) == -1)
return -1;
source = loopname;
}
mkdir(target, 0777);
char opts[256];
memset(opts, 0, sizeof(opts));
if (strlen(mount_opts) > (sizeof(opts) - 32)) {
}
strncpy(opts, mount_opts, sizeof(opts) - 32);
if (strcmp(fs, "iso9660") == 0) {
flags |= MS_RDONLY;
} else if (strncmp(fs, "ext", 3) == 0) {
bool has_remount_ro = false;
char* remount_ro_start = strstr(opts, "errors=remount-ro");
if (remount_ro_start != NULL) {
char after = *(remount_ro_start + strlen("errors=remount-ro"));
char before = remount_ro_start == opts ? '\0' : *(remount_ro_start - 1);
has_remount_ro = ((before == '\0' || before == ',') &&
(after == '\0' || after == ','));
}
if (strstr(opts, "errors=panic") || !has_remount_ro)
strcat(opts, ",errors=continue");
} else if (strcmp(fs, "xfs") == 0) {
strcat(opts, ",nouuid");
}
res = mount(source, target, fs, flags, opts);
if (res == -1) {
err = errno;
goto error_clear_loop;
}
res = open(target, O_RDONLY | O_DIRECTORY);
if (res == -1) {
err = errno;
goto error_clear_loop;
}
if (change_dir) {
res = chdir(target);
if (res == -1) {
err = errno;
}
}
error_clear_loop:
if (need_loop_device) {
ioctl(loopfd, LOOP_CLR_FD, 0);
close(loopfd);
}
errno = err;
return res;
}
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 reset_loop()
{
char buf[64];
snprintf(buf, sizeof(buf), "/dev/loop%llu", procid);
int loopfd = open(buf, O_RDWR);
if (loopfd != -1) {
ioctl(loopfd, LOOP_CLR_FD, 0);
close(loopfd);
}
}
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++) {
reset_loop();
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;
}
}
}
uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff};
void execute_one(void)
{
intptr_t res = 0;
res = syscall(__NR_pipe2, 0x20000100ul, 0ul);
if (res != -1) {
NONFAILING(r[0] = *(uint32_t*)0x20000100);
NONFAILING(r[1] = *(uint32_t*)0x20000104);
}
NONFAILING(memcpy((void*)0x20002080, "./file0\000", 8));
NONFAILING(syz_mount_image(0, 0x20002080, 0, 0, 0, 0, 0));
NONFAILING(memcpy((void*)0x200000c0,
"\x15\x06\x00\x00\x65\xff\xff\x00\x00\x00\x00\x08\x00\x39"
"\x50\x32\x30\x30\x30\x2e\x75",
21));
syscall(__NR_write, r[1], 0x200000c0ul, 0x15ul);
NONFAILING(*(uint32_t*)0x200001c4 = 0);
NONFAILING(*(uint32_t*)0x200001c8 = 0x10);
NONFAILING(*(uint32_t*)0x200001cc = 0);
NONFAILING(*(uint32_t*)0x200001d0 = 0);
NONFAILING(*(uint32_t*)0x200001d8 = -1);
NONFAILING(memset((void*)0x200001dc, 0, 12));
res = syscall(__NR_io_uring_setup, 0x5ec9, 0x200001c0ul);
if (res != -1)
r[2] = res;
syscall(__NR_close, r[2]);
NONFAILING(memcpy((void*)0x20000080, "./file0\000", 8));
NONFAILING(memcpy((void*)0x20000040, "9p\000", 3));
NONFAILING(memcpy((void*)0x20000140, "trans=fd,rfdno=", 15));
NONFAILING(sprintf((char*)0x2000014f, "0x%016llx", (long long)r[0]));
NONFAILING(memcpy((void*)0x20000161, ",wfdno=", 7));
NONFAILING(sprintf((char*)0x20000168, "0x%016llx", (long long)r[1]));
syscall(__NR_mount, 0ul, 0x20000080ul, 0x20000040ul, 0ul, 0x20000140ul);
}
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);
install_segv_handler();
loop();
return 0;
}
next prev parent reply other threads:[~2023-02-06 21:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-03 16:04 [PATCH v2] 9p/client: don't assume signal_pending() clears on recalc_sigpending() Jens Axboe
2023-02-05 10:02 ` Dominique Martinet
2023-02-06 20:19 ` Jens Axboe
2023-02-06 21:42 ` Dominique Martinet
2023-02-06 21:56 ` Jens Axboe [this message]
2023-02-06 21:58 ` Jens Axboe
2023-02-06 22:29 ` Dominique Martinet
2023-02-06 22:56 ` Jens Axboe
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