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pidfd: Cannot restore multiple processes pointing to a common dead pidfd #2496

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bsach64 opened this issue Oct 18, 2024 · 2 comments
Open

pidfd: Cannot restore multiple processes pointing to a common dead pidfd #2496

bsach64 opened this issue Oct 18, 2024 · 2 comments

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@bsach64
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bsach64 commented Oct 18, 2024 •
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Description
Please read the reproducer code: https://gist.github.com/bsach64/fcbdaec357fd7ed4212a86ac81b2e8bb

#define _GNU_SOURCE

#include <sys/statfs.h>
#include <stdio.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <sys/stat.h>

#ifndef PID_FS_MAGIC
#define PID_FS_MAGIC 0x50494446
#endif

/*
 * main
 *	`- child
 *		`- grandchild
 *
 * main and child open a pidfd for grandchild.
 * Before C/R we kill grandchild.
 * We end up with two pidfds in different process of
 * pointing to a common dead process.
 */

static int pidfd_open(pid_t pid, unsigned int flags)
{
	return syscall(__NR_pidfd_open, pid, flags);
}

static int pidfd_send_signal(int pidfd, int sig, siginfo_t* info, unsigned int flags)
{
	return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags);
}

int main(int argc, char* argv[])
{
	#define READ 0
	#define WRITE 1

	int child, ret, gchild, p[2], status, pidfd;

	if (pipe(p)) {
		perror("pipe");
		return 1;
	}

	child = fork();
	if (child < 0) {
		perror("fork");
		return 1;
	} else if (child == 0) {
		int gchild = fork();
		close(p[READ]);
		if (gchild < 0) {
			perror("fork");
			return 1;
		} else if (gchild == 0) {
			close(p[WRITE]);
			while(1)
				sleep(1000);
		} else {
			int pidfd;
			pidfd = pidfd_open(gchild, 0);
			if (pidfd < 0) {
				perror("pidfd_open");
				return 1;
			}

			if (write(p[WRITE], &gchild, sizeof(int)) != sizeof(int)) {
				printf("write");
				return 1;
			}

			close(p[WRITE]);
			if (waitpid(gchild, &status, 0) != gchild) {
				printf("waitpid");
				return 1;
			}

			while(1)
				sleep(1000);
		}
	}

	close(p[WRITE]);
	if (read(p[READ], &gchild, sizeof(int)) != sizeof(int)) {
		printf("write");
		return 1;
	}
	close(p[READ]);

	pidfd = pidfd_open(gchild, 0);
	if (pidfd < 0) {
		perror("pidfd_open");
		return 1;
	}

	/*
	* We kill grandchild processes only after opening pidfds.
	*/
	if (pidfd_send_signal(pidfd, SIGKILL, NULL, 0)) {
		perror("pidfd_send_signal");
		return 1;
	}
       /* Wait for C/R */
	while(1)
		sleep(1000);
}

Relevant Restore Failure Logs

(00.026088)  65165: Error (criu/pidfd.c:177): pidfd: Could not wait on temporary process with pid: 65616: No child processes
(00.026094)  65165: Error (criu/pidfd.c:245): pidfd: Failed to delete dead_pidfd struct
(00.026101)  65165: Error (criu/pidfd.c:261): pidfd: Can't create pidfd 0x000006 NSpid: -1 flags: 0
(00.026126)  65165: Error (criu/files.c:1221): Unable to open fd=3 id=0x6
(00.026167)  65166: Restore via sigreturn
(00.026192) Error (criu/cr-restore.c:2314): Restoring FAILED.
(00.026789) Error (criu/cr-restore.c:1261): 65165 killed by signal 9: Killed

I think the issue stems from the fact that the process that creates the tmp process is not the which is waiting for it.
A different process may kill this tmp process, but the one that creates it should be the one that waits for it to exit.
I will try to raise a PR with the fix over the next couple of weeks.

CRIU logs and information:

CRIU full restore logs: 

(00.000000) CRIU run id = 0xeffffffc0001004d
(00.000090) Version: 3.18 (gitid 59afbf343)
(00.000103) Running on fedora Linux 6.10.12-200.fc40.x86_64 #1 SMP PREEMPT_DYNAMIC Mon Sep 30 21:38:25 UTC 2024 x86_64
(00.000121) Loaded kdat cache from /run/criu.kdat
(00.000147) Hugetlb size 1024 Mb is supported but cannot get dev's number
(00.001057) cpu: x86_family 6 x86_vendor_id GenuineIntel x86_model_id 13th Gen Intel(R) Core(TM) i7-13700H
(00.001082) cpu: fpu: xfeatures_mask 0x205 xsave_size 2696 xsave_size_max 2696 xsaves_size 1664
(00.001090) cpu: fpu: x87 floating point registers     xstate_offsets      0 / 0      xstate_sizes    160 / 160   
(00.001095) cpu: fpu: AVX registers                    xstate_offsets    576 / 576    xstate_sizes    256 / 256   
(00.001099) cpu: fpu: Protection Keys User registers   xstate_offsets   2688 / 832    xstate_sizes      8 / 8     
(00.001131) rlimit: RLIMIT_NOFILE unlimited for self
(00.001278) cpu: fpu:1 fxsr:1 xsave:1 xsaveopt:1 xsavec:1 xgetbv1:1 xsaves:1
(00.001340) kernel pid_max=4194304
(00.001348) Reading image tree
(00.001385) Add mnt ns 6 pid 65165
(00.001391) Add net ns 2 pid 65165
(00.001395) Add pid ns 1 pid 65165
(00.001413) pstree pid_max=65166
(00.001425) Migrating process tree (SID 63706->63021)
(00.001430) Will restore in 0 namespaces
(00.001433) NS mask to use 0
(00.001472) Collecting 51/56 (flags 3)
(00.001481) No memfd.img image
(00.001485)  `- ... done
(00.001494) Collecting 40/54 (flags 2)
(00.001515) Collected [home/bsach/Code/criu-experiments/final/dead] ID 0x1
(00.001523) Collected [usr/lib64/libc.so.6] ID 0x2
(00.001528) Collected [usr/lib64/ld-linux-x86-64.so.2] ID 0x3
(00.001533) Collected [dev/pts/4] ID 0x5
(00.001547) pidfd: Collected : id 0x000006 flags 0 NSpid -1 ino 65467
(00.001559) Collected [home/bsach/Code/criu-experiments/final] ID 0x7
(00.001567) Collected [.] ID 0x8
(00.001572) pidfd: Collected : id 0x000009 flags 0 NSpid -1 ino 65467
(00.001578) Collected [home/bsach/Code/criu-experiments/final] ID 0xa
(00.001582) Collected [.] ID 0xb
(00.001588)  `- ... done
(00.001592) Collecting 46/69 (flags 0)
(00.001597) No remap-fpath.img image
(00.001601)  `- ... done
(00.001627) No apparmor.img image
(00.001673) cg: Preparing cgroups yard (cgroups restore mode 0x4)
(00.001864) cg: Opening .criu.cgyard.O6e57r as cg yard
(00.001884) cg: 	Making controller dir .criu.cgyard.O6e57r/unified (), type cgroup2
(00.001933) cg: Determined cgroup dir unified/user.slice/user-1000.slice/[email protected]/app.slice/app-foot.slice/app-foot-63705.scope already exist
(00.001944) cg: Skip restoring properties on cgroup dir unified/user.slice/user-1000.slice/[email protected]/app.slice/app-foot.slice/app-foot-63705.scope
(00.001972) cg: 	Making controller dir .criu.cgyard.O6e57r/zdtmtst (none,name=zdtmtst), type cgroup
(00.002130) cg: Determined cgroup dir zdtmtst/ already exist
(00.002137) cg: Skip restoring properties on cgroup dir zdtmtst/
(00.002159) cg: Determined cgroup dir zdtmtst//holder.8995a148-b632-4488-bc4e-13c6f56febd2 already exist
(00.002164) cg: Skip restoring properties on cgroup dir zdtmtst//holder.8995a148-b632-4488-bc4e-13c6f56febd2
(00.002180) cg: 	Making controller dir .criu.cgyard.O6e57r/zdtmtst.defaultroot (none,name=zdtmtst.defaultroot), type cgroup
(00.002262) cg: Determined cgroup dir zdtmtst.defaultroot/ already exist
(00.002269) cg: Skip restoring properties on cgroup dir zdtmtst.defaultroot/
(00.002287) cg: Determined cgroup dir zdtmtst.defaultroot//holder.8995a148-b632-4488-bc4e-13c6f56febd2 already exist
(00.002291) cg: Skip restoring properties on cgroup dir zdtmtst.defaultroot//holder.8995a148-b632-4488-bc4e-13c6f56febd2
(00.002639) Running pre-restore scripts
(00.002750) No pidns-1.img image
(00.002767) cg: cgroud: Daemon started
(00.002862) Forking task with 65165 pid (flags 0x0)
(00.002867) Creating process using clone3()
(00.003088) PID: real 65165 virt 65165
(00.003421)  65165: timens: monotonic -4 648245920
(00.003442)  65165: timens: boottime -4 648224914
(00.003533)  65165: cg: Move into 2
(00.003541)  65165: cg:   `-> unified//user.slice/user-1000.slice/[email protected]/app.slice/app-foot.slice/app-foot-63705.scope/cgroup.procs
(00.020445)  65165: cg:   `-> zdtmtst///cgroup.procs
(00.020553)  65165: cg:   `-> zdtmtst.defaultroot///cgroup.procs
(00.020598)  65165: Calling restore_sid() for init
(00.020652)  65165: Collecting 44/37 (flags 2)
(00.020744)  65165: tty: Collected tty ID 0x4 (pts)
(00.020778)  65165:  `- ... done
(00.020787)  65165: Collecting 45/51 (flags 0)
(00.020800)  65165: No tty-data.img image
(00.020822)  65165:  `- ... done
(00.020829)  65165: Restoring namespaces 65165 flags 0x0
(00.020874)  65165: Preparing info about shared resources
(00.020912)  65165: Collecting 48/38 (flags 0)
(00.020926)  65165: No filelocks.img image
(00.020933)  65165:  `- ... done
(00.020939)  65165: Collecting 42/27 (flags 0)
(00.020949)  65165: No pipes-data.img image
(00.020956)  65165:  `- ... done
(00.020962)  65165: Collecting 43/27 (flags 0)
(00.020972)  65165: No fifo-data.img image
(00.020978)  65165:  `- ... done
(00.020984)  65165: Collecting 41/70 (flags 0)
(00.020994)  65165: No sk-queues.img image
(00.021001)  65165:  `- ... done
(00.021091)  65165: Found 21 VMAs in image
(00.021107)  65165: vma 0x400000 0x401000
(00.021116)  65165: vma 0x401000 0x402000
(00.021122)  65165: vma 0x402000 0x403000
(00.021128)  65165: vma 0x403000 0x404000
(00.021134)  65165: vma 0x404000 0x405000
(00.021140)  65165: vma 0x7f13d6e2c000 0x7f13d6e2f000
(00.021147)  65165: vma 0x7f13d6e2f000 0x7f13d6e57000
(00.021153)  65165: vma 0x7f13d6e57000 0x7f13d6fc4000
(00.021159)  65165: vma 0x7f13d6fc4000 0x7f13d7012000
(00.021165)  65165: vma 0x7f13d7012000 0x7f13d7016000
(00.021171)  65165: vma 0x7f13d7016000 0x7f13d7018000
(00.021178)  65165: vma 0x7f13d7018000 0x7f13d7022000
(00.021184)  65165: vma 0x7f13d7034000 0x7f13d7038000
(00.021190)  65165: vma 0x7f13d7038000 0x7f13d703a000
(00.021196)  65165: vma 0x7f13d703a000 0x7f13d703b000
(00.021202)  65165: vma 0x7f13d703b000 0x7f13d7063000
(00.021208)  65165: vma 0x7f13d7063000 0x7f13d706d000
(00.021214)  65165: vma 0x7f13d706d000 0x7f13d706f000
(00.021219)  65165: vma 0x7f13d706f000 0x7f13d7071000
(00.021225)  65165: vma 0x7ffcc683f000 0x7ffcc6860000
(00.021231)  65165: vma 0xffffffffff600000 0xffffffffff601000
(00.021258)  65165: Collect fdinfo pid=65165 fd=0 id=0x4
(00.021270)  65165: Collect fdinfo pid=65165 fd=1 id=0x4
(00.021279)  65165: Collect fdinfo pid=65165 fd=2 id=0x4
(00.021286)  65165: Collect fdinfo pid=65165 fd=3 id=0x6
(00.021394)  65165: Found 21 VMAs in image
(00.021407)  65165: vma 0x400000 0x401000
(00.021415)  65165: vma 0x401000 0x402000
(00.021421)  65165: vma 0x402000 0x403000
(00.021427)  65165: vma 0x403000 0x404000
(00.021433)  65165: vma 0x404000 0x405000
(00.021439)  65165: vma 0x7f13d6e2c000 0x7f13d6e2f000
(00.021446)  65165: vma 0x7f13d6e2f000 0x7f13d6e57000
(00.021452)  65165: vma 0x7f13d6e57000 0x7f13d6fc4000
(00.021458)  65165: vma 0x7f13d6fc4000 0x7f13d7012000
(00.021464)  65165: vma 0x7f13d7012000 0x7f13d7016000
(00.021470)  65165: vma 0x7f13d7016000 0x7f13d7018000
(00.021476)  65165: vma 0x7f13d7018000 0x7f13d7022000
(00.021482)  65165: vma 0x7f13d7034000 0x7f13d7038000
(00.021488)  65165: vma 0x7f13d7038000 0x7f13d703a000
(00.021494)  65165: vma 0x7f13d703a000 0x7f13d703b000
(00.021500)  65165: vma 0x7f13d703b000 0x7f13d7063000
(00.021506)  65165: vma 0x7f13d7063000 0x7f13d706d000
(00.021512)  65165: vma 0x7f13d706d000 0x7f13d706f000
(00.021518)  65165: vma 0x7f13d706f000 0x7f13d7071000
(00.021524)  65165: vma 0x7ffcc683f000 0x7ffcc6860000
(00.021530)  65165: vma 0xffffffffff600000 0xffffffffff601000
(00.021552)  65165: Collect fdinfo pid=65166 fd=0 id=0x4
(00.021562)  65165: Collect fdinfo pid=65166 fd=1 id=0x4
(00.021570)  65165: Collect fdinfo pid=65166 fd=2 id=0x4
(00.021577)  65165: Collect fdinfo pid=65166 fd=3 id=0x9
(00.021608)  65165: Found two COW VMAs @0x400000-0x401000
(00.021618)  65165: Found two COW VMAs @0x401000-0x402000
(00.021624)  65165: Found two COW VMAs @0x402000-0x403000
(00.021630)  65165: Found two COW VMAs @0x403000-0x404000
(00.021636)  65165: Found two COW VMAs @0x404000-0x405000
(00.021678)  65165: Found two COW VMAs @0x7f13d6e2c000-0x7f13d6e2f000
(00.021688)  65165: Found two COW VMAs @0x7f13d6e2f000-0x7f13d6e57000
(00.021694)  65165: Found two COW VMAs @0x7f13d6e57000-0x7f13d6fc4000
(00.021700)  65165: Found two COW VMAs @0x7f13d6fc4000-0x7f13d7012000
(00.021706)  65165: Found two COW VMAs @0x7f13d7012000-0x7f13d7016000
(00.021712)  65165: Found two COW VMAs @0x7f13d7016000-0x7f13d7018000
(00.021718)  65165: Found two COW VMAs @0x7f13d7018000-0x7f13d7022000
(00.021724)  65165: Found two COW VMAs @0x7f13d7034000-0x7f13d7038000
(00.021730)  65165: Found two COW VMAs @0x7f13d7038000-0x7f13d703a000
(00.021736)  65165: Found two COW VMAs @0x7f13d703a000-0x7f13d703b000
(00.021742)  65165: Found two COW VMAs @0x7f13d703b000-0x7f13d7063000
(00.021748)  65165: Found two COW VMAs @0x7f13d7063000-0x7f13d706d000
(00.021753)  65165: Found two COW VMAs @0x7f13d706d000-0x7f13d706f000
(00.021759)  65165: Found two COW VMAs @0x7f13d706f000-0x7f13d7071000
(00.021765)  65165: Found two COW VMAs @0x7ffcc683f000-0x7ffcc6860000
(00.021875)  65165: skqueue: Preparing SCMs
(00.021886)  65165: tty: Unpaired slave 4
(00.021894)  65165: tty: ctl tty leader 0x4
(00.021900)  65165: tty: Inherit terminal for id 0x4
(00.021907)  65165: tty: head driver pts id 0x4 index 4 (master 0 sid 63706 pgrp 65165 inherit 1)
(00.021917)  65165: tty: Found orphan slave fake leader (0x4)
(00.021931)  65165: unix: ghost: Resolving addresses
(00.021939)  65165: File descs:
(00.021945)  65165:  `- type 1 ID 0x1
(00.021951)  65165:  `- type 1 ID 0x2
(00.021957)  65165:  `- type 1 ID 0x3
(00.021963)  65165:  `- type 11 ID 0x4
(00.021969)  65165:    `- FD 0 pid 65165
(00.021975)  65165:    `- FD 1 pid 65165
(00.021981)  65165:    `- FD 2 pid 65165
(00.021986)  65165:    `- FD 0 pid 65166
(00.021992)  65165:    `- FD 1 pid 65166
(00.021998)  65165:    `- FD 2 pid 65166
(00.022004)  65165:  `- type 1 ID 0x5
(00.022009)  65165:  `- type 20 ID 0x6
(00.022015)  65165:    `- FD 3 pid 65165
(00.022021)  65165:  `- type 1 ID 0x7
(00.022027)  65165:  `- type 1 ID 0x8
(00.022033)  65165:  `- type 20 ID 0x9
(00.022039)  65165:    `- FD 3 pid 65166
(00.022044)  65165:  `- type 1 ID 0xa
(00.022050)  65165:  `- type 1 ID 0xb
(00.022340)  65165: No parent images directory provided
(00.022515)  65165: Opened local page read 1 (parent 0)
(00.022664)  65165: 	premap 0x00000000400000-0x00000000401000 -> 00007f16cf600000
(00.022682)  65165: 	premap 0x00000000401000-0x00000000402000 -> 00007f16cf601000
(00.022693)  65165: 	premap 0x00000000402000-0x00000000403000 -> 00007f16cf602000
(00.022704)  65165: 	premap 0x00000000403000-0x00000000404000 -> 00007f16cf603000
(00.022715)  65165: 	premap 0x00000000404000-0x00000000405000 -> 00007f16cf604000
(00.022725)  65165: 	premap 0x007f13d6e2c000-0x007f13d6e2f000 -> 00007f16cf605000
(00.022791)  65165: 	premap 0x007f13d6e2f000-0x007f13d6e57000 -> 00007f16cf608000
(00.022804)  65165: 	premap 0x007f13d6e57000-0x007f13d6fc4000 -> 00007f16cf630000
(00.022818)  65165: 	premap 0x007f13d6fc4000-0x007f13d7012000 -> 00007f16cf79d000
(00.022845)  65165: 	premap 0x007f13d7012000-0x007f13d7016000 -> 00007f16cf7eb000
(00.022856)  65165: 	premap 0x007f13d7016000-0x007f13d7018000 -> 00007f16cf7ef000
(00.022867)  65165: 	premap 0x007f13d7018000-0x007f13d7022000 -> 00007f16cf7f1000
(00.022877)  65165: 	premap 0x007f13d7034000-0x007f13d7038000 -> 00007f16cf7fb000
(00.022887)  65165: 	premap 0x007f13d7038000-0x007f13d703a000 -> 00007f16cf7ff000
(00.022937)  65165: 	premap 0x007f13d703a000-0x007f13d703b000 -> 00007f16cf801000
(00.022951)  65165: 	premap 0x007f13d703b000-0x007f13d7063000 -> 00007f16cf802000
(00.022966)  65165: 	premap 0x007f13d7063000-0x007f13d706d000 -> 00007f16cf82a000
(00.022996)  65165: 	premap 0x007f13d706d000-0x007f13d706f000 -> 00007f16cf834000
(00.023016)  65165: 	premap 0x007f13d706f000-0x007f13d7071000 -> 00007f16cf836000
(00.023028)  65165: 	premap 0x007ffcc683f000-0x007ffcc6860000 -> 00007f16cf838000
(00.023035)  65165: pr65165-1 Read 401000 1 pages
(00.023043)  65165: pr65165-1 Read 403000 1 pages
(00.023089)  65165: pr65165-1 Read 404000 1 pages
(00.023095)  65165: pr65165-1 Read 7f13d6e2c000 2 pages
(00.023100)  65165: pr65165-1 Read 7f13d7012000 4 pages
(00.023105)  65165: pr65165-1 Read 7f13d7016000 2 pages
(00.023110)  65165: pr65165-1 Read 7f13d701c000 5 pages
(00.023115)  65165: pr65165-1 Read 7f13d7038000 2 pages
(00.023120)  65165: pr65165-1 Read 7f13d706d000 2 pages
(00.023125)  65165: pr65165-1 Read 7f13d706f000 2 pages
(00.023130)  65165: pr65165-1 Read 7ffcc685c000 4 pages
(00.023135)  65165: Read piov iovs 7, from 0, len 106496, first 0x7f16cf601000:4096
(00.023334)  65165: nr_restored_pages: 26
(00.023341)  65165: nr_shared_pages:   0
(00.023346)  65165: nr_dropped_pages:  0
(00.023350)  65165: nr_enqueued:       0
(00.023354)  65165: nr_lazy:           0
(00.023361)  65165: Restore on-core sigactions for 65165
(00.023419)  65165: Restoring children in alien sessions:
(00.023425)  65165: Restoring children in our session:
(00.023578)  65165: Forking task with 65166 pid (flags 0x0)
(00.023584)  65165: Creating process using clone3()
(00.024204)  65165: Restoring 65165 to 65165 pgid
(00.024230)  65165: 	will call setpgid, mine pgid is 65613
(00.024369)  65165: PID: real 65166 virt 65166
(00.024476)  65166: cg: Cgroups 2 inherited from parent
(00.024581)  65166: No parent images directory provided
(00.024650)  65166: Opened local page read 2 (parent 0)
(00.024713)  65166: 	premap 0x00000000400000-0x00000000401000 -> 00007f16cf200000
(00.024733)  65166: 	premap 0x00000000401000-0x00000000402000 -> 00007f16cf201000
(00.024746)  65166: 	premap 0x00000000402000-0x00000000403000 -> 00007f16cf202000
(00.024764)  65166: 	premap 0x00000000403000-0x00000000404000 -> 00007f16cf203000
(00.024779)  65166: 	premap 0x00000000404000-0x00000000405000 -> 00007f16cf204000
(00.024806)  65166: 	premap 0x007f13d6e2c000-0x007f13d6e2f000 -> 00007f16cf205000
(00.024822)  65166: 	premap 0x007f13d6e2f000-0x007f13d6e57000 -> 00007f16cf208000
(00.024836)  65166: 	premap 0x007f13d6e57000-0x007f13d6fc4000 -> 00007f16cf230000
(00.024850)  65166: 	premap 0x007f13d6fc4000-0x007f13d7012000 -> 00007f16cf39d000
(00.024870)  65166: 	premap 0x007f13d7012000-0x007f13d7016000 -> 00007f16cf3eb000
(00.024890)  65166: 	premap 0x007f13d7016000-0x007f13d7018000 -> 00007f16cf3ef000
(00.024910)  65166: 	premap 0x007f13d7018000-0x007f13d7022000 -> 00007f16cf3f1000
(00.024929)  65166: 	premap 0x007f13d7034000-0x007f13d7038000 -> 00007f16cf3fb000
(00.024955)  65166: 	premap 0x007f13d7038000-0x007f13d703a000 -> 00007f16cf3ff000
(00.024969)  65166: 	premap 0x007f13d703a000-0x007f13d703b000 -> 00007f16cf401000
(00.024984)  65166: 	premap 0x007f13d703b000-0x007f13d7063000 -> 00007f16cf402000
(00.025005)  65166: 	premap 0x007f13d7063000-0x007f13d706d000 -> 00007f16cf42a000
(00.025030)  65166: 	premap 0x007f13d706d000-0x007f13d706f000 -> 00007f16cf434000
(00.025042)  65166: 	premap 0x007f13d706f000-0x007f13d7071000 -> 00007f16cf436000
(00.025070)  65166: 	premap 0x007ffcc683f000-0x007ffcc6860000 -> 00007f16cf438000
(00.025078)  65166: pr65166-2 Read 401000 1 pages
(00.025083)  65166: 	pr65166-2 Read page from self 401000/0
(00.025098)  65166: pr65166-2 Read 403000 1 pages
(00.025102)  65166: 	pr65166-2 Read page from self 403000/1000
(00.025109)  65166: pr65166-2 Read 404000 1 pages
(00.025113)  65166: 	pr65166-2 Read page from self 404000/2000
(00.025124)  65166: pr65166-2 Read 7f13d6e2c000 1 pages
(00.025135)  65166: 	pr65166-2 Read page from self 7f13d6e2c000/3000
(00.025146)  65166: pr65166-2 Read 7f13d6e2d000 1 pages
(00.025150)  65166: 	pr65166-2 Read page from self 7f13d6e2d000/4000
(00.025157)  65166: pr65166-2 Read 7f13d7012000 1 pages
(00.025161)  65166: 	pr65166-2 Read page from self 7f13d7012000/5000
(00.025167)  65166: pr65166-2 Read 7f13d7013000 1 pages
(00.025171)  65166: 	pr65166-2 Read page from self 7f13d7013000/6000
(00.025178)  65166: pr65166-2 Read 7f13d7014000 1 pages
(00.025182)  65166: 	pr65166-2 Read page from self 7f13d7014000/7000
(00.025189)  65166: pr65166-2 Read 7f13d7015000 1 pages
(00.025192)  65166: 	pr65166-2 Read page from self 7f13d7015000/8000
(00.025223)  65166: pr65166-2 Read 7f13d7016000 1 pages
(00.025227)  65166: 	pr65166-2 Read page from self 7f13d7016000/9000
(00.025235)  65166: pr65166-2 Read 7f13d7017000 1 pages
(00.025239)  65166: 	pr65166-2 Read page from self 7f13d7017000/a000
(00.025246)  65166: pr65166-2 Read 7f13d701c000 1 pages
(00.025250)  65166: 	pr65166-2 Read page from self 7f13d701c000/b000
(00.025260)  65166: pr65166-2 Read 7f13d701d000 1 pages
(00.025264)  65166: 	pr65166-2 Read page from self 7f13d701d000/c000
(00.025271)  65166: pr65166-2 Read 7f13d701e000 1 pages
(00.025275)  65166: 	pr65166-2 Read page from self 7f13d701e000/d000
(00.025281)  65166: pr65166-2 Read 7f13d701f000 1 pages
(00.025286)  65166: 	pr65166-2 Read page from self 7f13d701f000/e000
(00.025292)  65166: pr65166-2 Read 7f13d7020000 1 pages
(00.025296)  65166: 	pr65166-2 Read page from self 7f13d7020000/f000
(00.025303)  65166: pr65166-2 Read 7f13d7038000 1 pages
(00.025317)  65166: 	pr65166-2 Read page from self 7f13d7038000/10000
(00.025330)  65166: pr65166-2 Read 7f13d7039000 1 pages
(00.025334)  65166: 	pr65166-2 Read page from self 7f13d7039000/11000
(00.025340)  65166: pr65166-2 Read 7f13d706d000 1 pages
(00.025344)  65166: 	pr65166-2 Read page from self 7f13d706d000/12000
(00.025350)  65166: pr65166-2 Read 7f13d706e000 1 pages
(00.025353)  65166: 	pr65166-2 Read page from self 7f13d706e000/13000
(00.025359)  65166: pr65166-2 Read 7f13d706f000 1 pages
(00.025363)  65166: 	pr65166-2 Read page from self 7f13d706f000/14000
(00.025373)  65166: pr65166-2 Read 7f13d7070000 1 pages
(00.025376)  65166: 	pr65166-2 Read page from self 7f13d7070000/15000
(00.025382)  65166: pr65166-2 Read 7ffcc685c000 1 pages
(00.025386)  65166: 	pr65166-2 Read page from self 7ffcc685c000/16000
(00.025392)  65166: pr65166-2 Read 7ffcc685d000 1 pages
(00.025395)  65166: 	pr65166-2 Read page from self 7ffcc685d000/17000
(00.025406)  65166: pr65166-2 Read 7ffcc685e000 1 pages
(00.025409)  65166: 	pr65166-2 Read page from self 7ffcc685e000/18000
(00.025416)  65166: pr65166-2 Read 7ffcc685f000 1 pages
(00.025419)  65166: 	pr65166-2 Read page from self 7ffcc685f000/19000
(00.025435)  65166: nr_restored_pages: 5
(00.025439)  65166: nr_shared_pages:   21
(00.025442)  65166: nr_dropped_pages:  0
(00.025446)  65166: nr_enqueued:       0
(00.025449)  65166: nr_lazy:           0
(00.025453)  65166: Restore on-core sigactions for 65166
(00.025485)  65166: Restoring children in alien sessions:
(00.025490)  65166: Restoring children in our session:
(00.025518)  65166: Restoring 65166 to 65165 pgid
(00.025525)  65166: 	will call setpgid, mine pgid is 65613
(00.025561)  65165: Restoring resources
(00.025574)  65166: Restoring resources
(00.025588)  65165: Opening fdinfo-s
(00.025596)  65166: Opening fdinfo-s
(00.025597)  65165: tty: open driver pts id 0x4 index 4 (master 0 sid 63706 pgrp 65165 inherit 1)
(00.025604)  65166: 	Receive fd for 0
(00.025614)  65166: 	Receive fd for 1
(00.025618)  65166: 	Receive fd for 2
(00.025619)  65165: tty: Migrated slave peer 0x4 -> to fd 0
(00.025653)  65165: 		Create fd for 0
(00.025657)  65165: 			Going to dup 0 into 1
(00.025663)  65165: 			Going to dup 0 into 2
(00.025668)  65165: 		Send fd 0 to /crtools-fd-65166-effffffc0001004d
(00.025684)  65165: 		Send fd 0 to /crtools-fd-65166-effffffc0001004d
(00.025690)  65165: 		Send fd 0 to /crtools-fd-65166-effffffc0001004d
(00.025697)  65165: 	Receive fd for 1
(00.025701)  65165: 	Receive fd for 2
(00.026020)  65166: 		Create fd for 3
(00.026040)  65166: 	Receive fd for 0
(00.026052)  65166: Further fle=0x7f16d0381c38, pid=65166
(00.026056)  65166: 	Receive fd for 1
(00.026063)  65166: Further fle=0x7f16d0381c78, pid=65166
(00.026067)  65166: 	Receive fd for 2
(00.026073)  65166: Further fle=0x7f16d0381cb8, pid=65166
(00.026088)  65165: Error (criu/pidfd.c:177): pidfd: Could not wait on temporary process with pid: 65616: No child processes
(00.026094)  65165: Error (criu/pidfd.c:245): pidfd: Failed to delete dead_pidfd struct
(00.026101)  65165: Error (criu/pidfd.c:261): pidfd: Can't create pidfd 0x000006 NSpid: -1 flags: 0
(00.026126)  65165: Error (criu/files.c:1221): Unable to open fd=3 id=0x6
(00.026167)  65166: Restore via sigreturn
(00.026192) Error (criu/cr-restore.c:2314): Restoring FAILED.
(00.026789) Error (criu/cr-restore.c:1261): 65165 killed by signal 9: Killed
(00.027685) Error (criu/cgroup.c:1998): cg: cgroupd: recv req error: No such file or directory

@rst0git
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rst0git commented Oct 18, 2024

@bsach64 Thank you for working on this!

Would it be possible to create a page describing how checkpoint/restore of pidfd works in https://criu.org/Category:Under_the_hood?

@bsach64
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bsach64 commented Oct 18, 2024

@bsach64 Thank you for working on this!

Would it be possible to create a page describing how checkpoint/restore of pidfd works in https://criu.org/Category:Under_the_hood?

Sure @rst0git! I will do so in the near future!

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