Decode process_mrelease syscall

Introduced by Linux commits v5.14-159-g884a7e5964e0
and v5.14-160-gdce491039628.

* src/linux/generic/syscallent-common.h ([BASE_NR + 448]): Add
process_mrelease syscall entry.
* src/mem.c (SYS_FUNC(process_mrelease)): New syscall decoder.
* tests/.gitignore: Add process_mrelease and process_mrelease-y.
* tests/gen_tests.in (process_mrelease, process_mrelease-y): New tests.
* tests/process_mrelease.c: New file.
* tests/process_mrelease-y.c: Likewise.
* NEWS: Mention it.

8 files changed, 84 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 65459be4b..f0a8843f2 100644
--- a/NEWS
+++ b/NEWS
@@ -5,6 +5,7 @@ Noteworthy changes in release ?.?? (????-??-??)
   * Improved printing of syscall names in places where the associated
     AUDIT_ARCH_* value is present (ptrace PTRACE_GET_SYSCALL_INFO request,
     SIGSYS siginfo_t).
+  * Implemented decoding of process_mrelease syscall, introduced in Linux 5.15.
   * Implemented decoding of SECCOMP_GET_NOTIF_SIZES operation of seccomp
     syscall.
   * Implemented decoding of SECCOMP_* ioctl commands.
diff --git a/src/linux/generic/syscallent-common.h b/src/linux/generic/syscallent-common.h
index b5498f1d6..124e505ea 100644
--- a/src/linux/generic/syscallent-common.h
+++ b/src/linux/generic/syscallent-common.h
@@ -32,3 +32,4 @@
 [BASE_NR + 445] = { 4,	TD,		SEN(landlock_add_rule),		"landlock_add_rule"		},
 [BASE_NR + 446] = { 2,	TD,		SEN(landlock_restrict_self),	"landlock_restrict_self"	},
 [BASE_NR + 447] = { 1,	TD,		SEN(memfd_secret),		"memfd_secret"			},
+[BASE_NR + 448] = { 2,	TD,		SEN(process_mrelease),		"process_mrelease"	},
diff --git a/src/mem.c b/src/mem.c
index d8382af5f..d34a92118 100644
--- a/src/mem.c
+++ b/src/mem.c
@@ -319,6 +319,19 @@ SYS_FUNC(process_madvise)
 	return RVAL_DECODED;
 }
 
+SYS_FUNC(process_mrelease)
+{
+	const int pidfd = tcp->u_arg[0];
+	const unsigned int flags = tcp->u_arg[1];
+
+	printfd(tcp, pidfd);
+	tprint_arg_next();
+
+	PRINT_VAL_X(flags);
+
+	return RVAL_DECODED;
+}
+
 #include "xlat/mlockall_flags.h"
 
 SYS_FUNC(mlockall)
diff --git a/tests/.gitignore b/tests/.gitignore
index 237c7c597..8cd778abc 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -708,6 +708,8 @@ prlimit64-success--pidns-translation
 process_madvise
 process_madvise-y
 process_madvise-yy
+process_mrelease
+process_mrelease-y
 process_vm_readv
 process_vm_readv--pidns-translation
 process_vm_writev
diff --git a/tests/gen_tests.in b/tests/gen_tests.in
index 06af2de6f..f547d61b4 100644
--- a/tests/gen_tests.in
+++ b/tests/gen_tests.in
@@ -675,6 +675,8 @@ prlimit64-success--pidns-translation	check_scno_tampering; test_pidns -a36 -einj
 process_madvise
 process_madvise-y	--trace=process_madvise -y
 process_madvise-yy	--trace=process_madvise -yy
+process_mrelease	-a24
+process_mrelease-y	-e trace=process_mrelease -y -a24 </dev/full
 process_vm_readv	-s5 -a37
 process_vm_readv--pidns-translation	test_pidns -s5 -a37 -e trace=process_vm_readv
 process_vm_writev	-s5 -a38
diff --git a/tests/process_mrelease-y.c b/tests/process_mrelease-y.c
new file mode 100644
index 000000000..600cd195f
--- /dev/null
+++ b/tests/process_mrelease-y.c
@@ -0,0 +1,4 @@
+#define SKIP_IF_PROC_IS_UNAVAILABLE skip_if_unavailable("/proc/self/fd/")
+#define FD0_STR "</dev/full>"
+
+#include "process_mrelease.c"
diff --git a/tests/process_mrelease.c b/tests/process_mrelease.c
new file mode 100644
index 000000000..b7c34d3ae
--- /dev/null
+++ b/tests/process_mrelease.c
@@ -0,0 +1,59 @@
+/*
+ * Check decoding of process_mrelease syscall.
+ *
+ * Copyright (c) 2021 Eugene Syromyatnikov <evgsyr@gmail.com>
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "tests.h"
+#include "scno.h"
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#ifndef SKIP_IF_PROC_IS_UNAVAILABLE
+# define SKIP_IF_PROC_IS_UNAVAILABLE
+#endif
+
+#ifndef FD0_STR
+# define FD0_STR ""
+#endif
+
+static const char *errstr;
+
+static long
+sys_process_mrelease(int pidfd, unsigned int flags)
+{
+	static const kernel_ulong_t fill =
+		(kernel_ulong_t) 0xbadc0ded00000000ULL;
+	kernel_ulong_t arg1 = fill | (unsigned int) pidfd;
+	kernel_ulong_t arg2 = fill | flags;
+	kernel_ulong_t arg3 = fill | 0xdeedefed;
+	kernel_ulong_t arg4 = fill | 0xdebeefed;
+	kernel_ulong_t arg5 = fill | 0xdecaffed;
+	kernel_ulong_t arg6 = fill | 0xdeefaced;
+
+	long rc = syscall(__NR_process_mrelease,
+			  arg1, arg2, arg3, arg4, arg5, arg6);
+	errstr = sprintrc(rc);
+	return rc;
+}
+
+int
+main(void)
+{
+	SKIP_IF_PROC_IS_UNAVAILABLE;
+
+	sys_process_mrelease(-1, 0);
+	printf("process_mrelease(-1, 0) = %s\n", errstr);
+
+	sys_process_mrelease(0, 0xfacefeed);
+	printf("process_mrelease(0" FD0_STR ", 0xfacefeed) = %s\n", errstr);
+
+	puts("+++ exited with 0 +++");
+	return 0;
+}
diff --git a/tests/pure_executables.list b/tests/pure_executables.list
index 436180971..fee99dd60 100755
--- a/tests/pure_executables.list
+++ b/tests/pure_executables.list
@@ -504,6 +504,8 @@ prlimit64
 process_madvise
 process_madvise-y
 process_madvise-yy
+process_mrelease
+process_mrelease-y
 process_vm_readv
 process_vm_writev
 pselect6