[CRIU] [PATCH v3] rework criu check logic
Pavel Emelyanov
xemul at virtuozzo.com
Sun Mar 20 23:31:45 PDT 2016
Applied, thanks a LOT, Saied :)
The patch conflicted with the autofs bits merged earlier. I've put
the "autofs" checks into category 2 -- the kernel features, that are
not _yet_ in the upstream. Stas, am I right, that the check_autofs()
stuff checks the functionality that hasn't yet hit Linus' tree?
-- Pavel
On 03/17/2016 12:38 AM, Saied Kazemi wrote:
> The "criu check" command to check if the kernel is properly configured
> to run criu is broken.
>
> The "criu check --ms" command used to be the way to tell criu to check
> only for features that have been merged upstream. But recent kernels
> have a set of features whose presence doesn't necessarily mean that
> dump or restore will fail but rather *may* fail depending on whether
> the process tree uses those features.
>
> This patch deprecates --ms and introduces --extra, --experimental,
> and --all. See "criu --help" or "man criu" for more info.
>
> Typical use cases are:
>
> $ sudo criu check
> <zero or more warnings and errors...>
> Looks good.
> $ echo $?
> 0
>
> $ sudo criu check --extra
> <zero or more warnings and errors...>
> Looks good.
> $ echo $?
> 1
>
> $ sudo criu check --extra
> <one or more warnings...>
> Looks good but some kernel features are missing
> which, depending on your process tree, may cause
> dump or restore failure.
> $ echo $?
> 1
>
> $ sudo criu check --feature list
> mnt_id aio_remap timerfd tun userns fdinfo_lock seccomp_suspend \
> seccomp_filters loginuid cgroupns
>
> $ sudo criu check --feature mnt_id
> Warn (cr-check.c:283): fdinfo doesn't contain the mnt_id field
> $ echo $?
> 1
>
> $ sudo criu check --feature tun
> tun is supported
> $ echo $?
> 0
>
> Signed-off-by: Saied Kazemi <saied at google.com>
> ---
> Documentation/criu.txt | 48 ++++++++--
> criu/cr-check.c | 237 ++++++++++++++++++++++++++++++----------------
> criu/cr-service.c | 3 -
> criu/crtools.c | 40 ++++++--
> criu/include/cr_options.h | 3 +-
> 5 files changed, 232 insertions(+), 99 deletions(-)
>
> diff --git a/Documentation/criu.txt b/Documentation/criu.txt
> index e7ba6dd..77eb5be 100644
> --- a/Documentation/criu.txt
> +++ b/Documentation/criu.txt
> @@ -314,15 +314,51 @@ relaxing capability with *--cpu-cap*=*none* parameter.
>
> *check*
> ~~~~~~~
> -Tests whether the kernel support is up to date.
> +Checks whether the kernel supports the features that *criu* needs to
> +successfully dump and restore a process tree.
>
> -*--ms*::
> - Do not check not yet merged features.
> +There are three categories of kernel support as described below. *criu
> +check* always checks Category 1 features unless *--feature* is specified
> +which only checks the specified feature.
> +
> +- *Category 1*. Absolutely required. These are features like
> + '/proc/<pid>/map_files', 'NETLINK_SOCK_DIAG' socket
> + monitoring, '/proc/sys/kernel/ns_last_pid', etc.
> +
> +- *Category 2*. Required only for specific cases. These are features
> + like aio remap, '/dev/net/tun', etc. that are
> + required if the process being dumped or restored
> + is using them.
> +
> +- *Category 3*. Experimental. These are features like task-diag that
> + are used for experimental purposes (mostly
> + during development).
> +
> +If there are no errors or warnings, *criu* prints "Looks good." and its
> +exit code will be 0.
> +
> +A missing Category 1 feature causes *criu* to print "Does not look good."
> +and its exit code will be non-zero.
> +
> +Missing Category 2 and 3 features cause *criu* to print "Looks good but
> +some kernel features are missing which, depending on your process tree,
> +may cause dump or restore failure." and its exit code will be non-zero.
> +
> +Without an argument, *criu check* checks Category 1 features. This
> +behavior can change with the following options:
> +
> +*--extra*::
> + Check kernel support for Category 2 features.
> +
> +*--experimental*::
> + Check kernel support for Category 3 features.
> +
> +*--all*::
> + Check kernel support for Category 1, 2, and 3 features.
>
> *--feature* '<name>'::
> - Check a particular feature. Instead of checking everything one may specify
> - which exactly feature is to be tested. The '<name>' may be: *mnt_id*,
> - *aio_remap*, *timerfd*, *tun*, *userns*.
> + Check a specific feature. If '<name>' is 'list', a list of valid
> + kernel feature names that can be checked will be printed.
>
> *page-server*
> ~~~~~~~~~~~~~
> diff --git a/criu/cr-check.c b/criu/cr-check.c
> index ea03684..428116a 100644
> --- a/criu/cr-check.c
> +++ b/criu/cr-check.c
> @@ -41,6 +41,8 @@
> #include "pstree.h"
> #include "cr_options.h"
>
> +static char *feature_name(int (*func)());
> +
> static int check_tty(void)
> {
> int master = -1, slave = -1;
> @@ -169,7 +171,7 @@ static int check_kcmp(void)
> return 0;
> }
>
> -static int check_prctl(void)
> +static int check_prctl_cat1(void)
> {
> unsigned long user_auxv = 0;
> unsigned int *tid_addr;
> @@ -183,23 +185,18 @@ static int check_prctl(void)
> }
>
> /*
> - * Either new or old interface must be supported in the kernel.
> + * It's OK if the new interface is not supported because it's
> + * a Category 2 feature, but the old interface has to be supported.
> */
> ret = prctl(PR_SET_MM, PR_SET_MM_MAP_SIZE, (unsigned long)&size, 0, 0);
> if (ret < 0) {
> - if (!opts.check_ms_kernel) {
> - pr_msg("prctl: PR_SET_MM_MAP is not supported, which "
> - "is required for restoring user namespaces: %m\n");
> - return -1;
> - } else
> - pr_warn("Skipping unssuported PR_SET_MM_MAP: %m\n");
> -
> + pr_msg("Info prctl: PR_SET_MM_MAP_SIZE is not supported\n");
> ret = prctl(PR_SET_MM, PR_SET_MM_BRK, (unsigned long)sbrk(0), 0, 0);
> if (ret < 0) {
> if (errno == EPERM)
> pr_msg("prctl: One needs CAP_SYS_RESOURCE capability to perform testing\n");
> else
> - pr_msg("prctl: PR_SET_MM is not supported: %m\n");
> + pr_msg("prctl: PR_SET_MM_BRK is not supported: %m\n");
> return -1;
> }
>
> @@ -219,6 +216,19 @@ static int check_prctl(void)
> return 0;
> }
>
> +static int check_prctl_cat2(void)
> +{
> + unsigned int size = 0;
> + int ret;
> +
> + ret = prctl(PR_SET_MM, PR_SET_MM_MAP_SIZE, (unsigned long)&size, 0, 0);
> + if (ret) {
> + pr_warn("prctl: PR_SET_MM_MAP_SIZE is not supported\n");
> + return -1;
> + }
> + return 0;
> +}
> +
> static int check_fcntl(void)
> {
> u32 v[2];
> @@ -766,11 +776,8 @@ static int check_aio_remap(void)
> ctx = (aio_context_t)naddr;
> r = syscall(SYS_io_getevents, ctx, 0, 1, NULL, NULL);
> if (r < 0) {
> - if (!opts.check_ms_kernel) {
> - pr_err("AIO remap doesn't work properly: %m\n");
> - return -1;
> - } else
> - pr_warn("Skipping unsupported AIO remap: %m\n");
> + pr_err("AIO remap doesn't work properly: %m\n");
> + return -1;
> }
>
> return 0;
> @@ -782,12 +789,8 @@ static int check_fdinfo_lock(void)
> return -1;
>
> if (!kdat.has_fdinfo_lock) {
> - if (!opts.check_ms_kernel) {
> - pr_err("fdinfo doesn't contain the lock field\n");
> - return -1;
> - } else {
> - pr_warn("fdinfo doesn't contain the lock field\n");
> - }
> + pr_err("fdinfo doesn't contain the lock field\n");
> + return -1;
> }
>
> return 0;
> @@ -823,10 +826,6 @@ static int check_clone_parent_vs_pid()
> static int check_cgroupns(void)
> {
> int ret;
> - if (opts.check_ms_kernel) {
> - pr_warn("Skipping cgroup namespaces check\n");
> - return 0;
> - }
>
> ret = access("/proc/self/ns/cgroup", F_OK);
> if (ret < 0) {
> @@ -839,6 +838,29 @@ static int check_cgroupns(void)
>
> static int (*chk_feature)(void);
>
> +/*
> + * There are three categories of kernel features:
> + *
> + * 1. Absolutely required (/proc/pid/map_files, ptrace PEEKSIGINFO, etc.).
> + * 2. Required only for specific cases (aio remap, tun, etc.).
> + * Checked when --extra or --all is specified.
> + * 3. Experimental (task-diag).
> + * Checked when --experimental or --all is specified.
> + *
> + * We fail if any feature in category 1 is missing but tolerate failures
> + * in the other categories. Currently, there is nothing in category 3.
> + */
> +#define CHECK_GOOD "Looks good."
> +#define CHECK_BAD "Does not look good."
> +#define CHECK_MAYBE "Looks good but some kernel features are missing\n" \
> + "which, depending on your process tree, may cause\n" \
> + "dump or restore failure."
> +#define CHECK_CAT1(fn) do { \
> + if ((ret = fn) != 0) { \
> + print_on_level(DEFAULT_LOGLEVEL, "%s\n", CHECK_BAD); \
> + return ret; \
> + } \
> + } while (0)
> int cr_check(void)
> {
> struct ns_id ns = { .type = NS_CRIU, .ns_pid = PROC_SELF, .nd = &mnt_ns_desc };
> @@ -863,44 +885,74 @@ int cr_check(void)
> return -1;
>
> if (chk_feature) {
> - ret = chk_feature();
> - goto out;
> + if (chk_feature())
> + return -1;
> + print_on_level(DEFAULT_LOGLEVEL, "%s is supported\n",
> + feature_name(chk_feature));
> + return 0;
> }
>
> - ret |= check_map_files();
> - ret |= check_sock_diag();
> - ret |= check_ns_last_pid();
> - ret |= check_sock_peek_off();
> - ret |= check_kcmp();
> - ret |= check_prctl();
> - ret |= check_fcntl();
> - ret |= check_proc_stat();
> - ret |= check_tcp();
> - ret |= check_fdinfo_ext();
> - ret |= check_unaligned_vmsplice();
> - ret |= check_tty();
> - ret |= check_so_gets();
> - ret |= check_ipc();
> - ret |= check_sigqueuinfo();
> - ret |= check_ptrace_peeksiginfo();
> - ret |= check_ptrace_suspend_seccomp();
> - ret |= check_ptrace_dump_seccomp_filters();
> - ret |= check_mem_dirty_track();
> - ret |= check_posix_timers();
> - ret |= check_tun_cr(0);
> - ret |= check_timerfd();
> - ret |= check_mnt_id();
> - ret |= check_aio_remap();
> - ret |= check_fdinfo_lock();
> - ret |= check_clone_parent_vs_pid();
> - ret |= check_cgroupns();
> + /*
> + * Category 1 - absolutely required.
> + * So that the user can see clearly what's missing, we exit with
> + * non-zero status on the first failure because it gets very
> + * confusing when there are many warnings and error messages.
> + */
> + CHECK_CAT1(check_map_files());
> + CHECK_CAT1(check_sock_diag());
> + CHECK_CAT1(check_ns_last_pid());
> + CHECK_CAT1(check_sock_peek_off());
> + CHECK_CAT1(check_kcmp());
> + CHECK_CAT1(check_prctl_cat1());
> + CHECK_CAT1(check_fcntl());
> + CHECK_CAT1(check_proc_stat());
> + CHECK_CAT1(check_tcp());
> + CHECK_CAT1(check_fdinfo_ext());
> + CHECK_CAT1(check_unaligned_vmsplice());
> + CHECK_CAT1(check_tty());
> + CHECK_CAT1(check_so_gets());
> + CHECK_CAT1(check_ipc());
> + CHECK_CAT1(check_sigqueuinfo());
> + CHECK_CAT1(check_ptrace_peeksiginfo());
> +
> + /*
> + * Category 2 - required for specific cases.
> + * Unlike Category 1 features, we don't exit with non-zero status
> + * on a failure because CRIU may still work.
> + */
> + if (opts.check_extra_features) {
> + ret |= check_prctl_cat2();
> + ret |= check_ptrace_suspend_seccomp();
> + ret |= check_ptrace_dump_seccomp_filters();
> + ret |= check_mem_dirty_track();
> + ret |= check_posix_timers();
> + ret |= check_tun_cr(0);
> + ret |= check_timerfd();
> + ret |= check_mnt_id();
> + ret |= check_aio_remap();
> + ret |= check_fdinfo_lock();
> + ret |= check_clone_parent_vs_pid();
> + ret |= check_cgroupns();
> + }
>
> -out:
> - if (!ret)
> - print_on_level(DEFAULT_LOGLEVEL, "Looks good.\n");
> + /*
> + * Category 3 - experimental.
> + */
> + if (opts.check_experimental_features) {
> + /*
> + * Place holder as currently there are no checks.
> + * Remove this comment when adding checks for
> + * experimental features.
> + */
> + }
>
> + print_on_level(DEFAULT_LOGLEVEL, "%s\n", ret ? CHECK_MAYBE : CHECK_GOOD);
> return ret;
> }
> +#undef CHECK_GOOD
> +#undef CHECK_BAD
> +#undef CHECK_MAYBE
> +#undef CHECK_CAT1
>
> static int check_tun(void)
> {
> @@ -926,7 +978,7 @@ static int check_userns(void)
>
> ret = prctl(PR_SET_MM, PR_SET_MM_MAP_SIZE, (unsigned long)&size, 0, 0);
> if (ret < 0) {
> - pr_perror("No new prctl API");
> + pr_perror("prctl: PR_SET_MM_MAP_SIZE is not supported");
> return -1;
> }
>
> @@ -946,32 +998,53 @@ static int check_loginuid(void)
> return 0;
> }
>
> +struct feature_list {
> + char *name;
> + int (*func)();
> +};
> +
> +static struct feature_list feature_list[] = {
> + { "mnt_id", check_mnt_id },
> + { "aio_remap", check_aio_remap },
> + { "timerfd", check_timerfd },
> + { "tun", check_tun },
> + { "userns", check_userns },
> + { "fdinfo_lock", check_fdinfo_lock },
> + { "seccomp_suspend", check_ptrace_suspend_seccomp },
> + { "seccomp_filters", check_ptrace_dump_seccomp_filters },
> + { "loginuid", check_loginuid },
> + { "cgroupns", check_cgroupns },
> + { NULL, NULL },
> +};
> +
> int check_add_feature(char *feat)
> {
> - if (!strcmp(feat, "mnt_id"))
> - chk_feature = check_mnt_id;
> - else if (!strcmp(feat, "aio_remap"))
> - chk_feature = check_aio_remap;
> - else if (!strcmp(feat, "timerfd"))
> - chk_feature = check_timerfd;
> - else if (!strcmp(feat, "tun"))
> - chk_feature = check_tun;
> - else if (!strcmp(feat, "userns"))
> - chk_feature = check_userns;
> - else if (!strcmp(feat, "fdinfo_lock"))
> - chk_feature = check_fdinfo_lock;
> - else if (!strcmp(feat, "seccomp_suspend"))
> - chk_feature = check_ptrace_suspend_seccomp;
> - else if (!strcmp(feat, "seccomp_filters"))
> - chk_feature = check_ptrace_dump_seccomp_filters;
> - else if (!strcmp(feat, "loginuid"))
> - chk_feature = check_loginuid;
> - else if (!strcmp(feat, "cgroupns"))
> - chk_feature = check_cgroupns;
> - else {
> - pr_err("Unknown feature %s\n", feat);
> - return -1;
> + struct feature_list *fl;
> +
> + if (!strcmp(feat, "list")) {
> + for (fl = feature_list; fl->name; fl++)
> + pr_msg("%s ", fl->name);
> + pr_msg("\n");
> + return 1;
> }
>
> - return 0;
> + for (fl = feature_list; fl->name; fl++) {
> + if (!strcmp(feat, fl->name)) {
> + chk_feature = fl->func;
> + return 0;
> + }
> + }
> + pr_err("Unknown feature %s\n", feat);
> + return -1;
> +}
> +
> +static char *feature_name(int (*func)())
> +{
> + struct feature_list *fl;
> +
> + for (fl = feature_list; fl->func; fl++) {
> + if (fl->func == func)
> + return fl->name;
> + }
> + return NULL;
> }
> diff --git a/criu/cr-service.c b/criu/cr-service.c
> index 88d4af7..032c763 100644
> --- a/criu/cr-service.c
> +++ b/criu/cr-service.c
> @@ -567,9 +567,6 @@ static int check(int sk)
>
> setproctitle("check --rpc");
>
> - /* Check only minimal kernel support */
> - opts.check_ms_kernel = true;
> -
> if (!cr_check())
> resp.success = true;
>
> diff --git a/criu/crtools.c b/criu/crtools.c
> index 800fa6d..85c06a3 100644
> --- a/criu/crtools.c
> +++ b/criu/crtools.c
> @@ -319,6 +319,9 @@ int main(int argc, char *argv[], char *envp[])
> { "external", required_argument, 0, 1073 },
> { "empty-ns", required_argument, 0, 1074 },
> { "unshare", required_argument, 0, 1075 },
> + { "extra", no_argument, 0, 1076 },
> + { "experimental", no_argument, 0, 1077 },
> + { "all", no_argument, 0, 1078 },
> { },
> };
>
> @@ -499,8 +502,8 @@ int main(int argc, char *argv[], char *envp[])
> opts.force_irmap = true;
> break;
> case 1054:
> - opts.check_ms_kernel = true;
> - break;
> + pr_err("--ms is deprecated; see \"Check options\" of criu --help\n");
> + return 1;
> case 'L':
> opts.libdir = optarg;
> break;
> @@ -534,8 +537,11 @@ int main(int argc, char *argv[], char *envp[])
> return 1;
> break;
> case 1063:
> - if (check_add_feature(optarg) < 0)
> + ret = check_add_feature(optarg);
> + if (ret < 0) /* invalid kernel feature name */
> return 1;
> + if (ret > 0) /* list kernel features and exit */
> + return 0;
> break;
> case 1064:
> if (!add_skip_mount(optarg))
> @@ -602,6 +608,16 @@ int main(int argc, char *argv[], char *envp[])
> return 1;
> }
> break;
> + case 1076:
> + opts.check_extra_features = true;
> + break;
> + case 1077:
> + opts.check_experimental_features = true;
> + break;
> + case 1078:
> + opts.check_extra_features = true;
> + opts.check_experimental_features = true;
> + break;
> case 'V':
> pr_msg("Version: %s\n", CRIU_VERSION);
> if (strcmp(CRIU_GITID, "0"))
> @@ -763,7 +779,7 @@ usage:
> "Usage:\n"
> " criu dump|pre-dump -t PID [<options>]\n"
> " criu restore [<options>]\n"
> -" criu check [--ms]\n"
> +" criu check [--feature FEAT]\n"
> " criu exec -p PID <syscall-string>\n"
> " criu page-server\n"
> " criu service [<options>]\n"
> @@ -857,8 +873,19 @@ usage:
> " socket[inode]\n"
> " file[mnt_id:inode]\n"
> " --empty-ns {net}\n"
> -" Create a namespace, but don't restore its properies.\n"
> -" An user will retore them from action scripts.\n"
> +" Create a namespace, but don't restore its properies.\n"
> +" An user will retore them from action scripts.\n"
> +"Check options:\n"
> +" without any arguments, \"criu check\" checks availability of absolutely required\n"
> +" kernel features; if any of these features is missing dump and restore will fail\n"
> +" --extra also check availability of extra kernel features\n"
> +" --experimental also check availability of experimental kernel features\n"
> +" --all also check availability of extra and experimental kernel features\n"
> +" --feature FEAT only check availability of one of the following kernel features\n"
> +" "
> + );
> + check_add_feature("list");
> + pr_msg(
> "\n"
> "* Logging:\n"
> " -o|--log-file FILE log file name\n"
> @@ -886,7 +913,6 @@ usage:
> "Other options:\n"
> " -h|--help show this text\n"
> " -V|--version show version\n"
> -" --ms don't check not yet merged kernel features\n"
> );
>
> return 0;
> diff --git a/criu/include/cr_options.h b/criu/include/cr_options.h
> index c1e8fbc..17eb0f0 100644
> --- a/criu/include/cr_options.h
> +++ b/criu/include/cr_options.h
> @@ -56,7 +56,8 @@ struct cr_options {
> int final_state;
> char *show_dump_file;
> char *show_fmt;
> - bool check_ms_kernel;
> + bool check_extra_features;
> + bool check_experimental_features;
> bool show_pages_content;
> union {
> bool restore_detach;
>
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