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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-14 16:35:39 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-14 16:35:39 -0800 |
| commit | 6d93a1971a0ded67887eeab8d00a02074490f071 (patch) | |
| tree | 7dc6494bde2dec7fc2ddf6ef4bd09f8d5778757e /fs/proc | |
| parent | 0ca2ce81eb8ee30f3ba8ac7967fef9cfbb44dbdb (diff) | |
| parent | 5c62634fc65101d350cbd47722fb76f02693059d (diff) | |
Merge tag 'time-namespace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull time namespace updates from Christian Brauner:
"When time namespaces were introduced we missed to virtualize the
'btime' field in /proc/stat. This confuses tasks which are in another
time namespace with a virtualized boottime which is common in some
container workloads. This contains Michael's series to fix 'btime'
which Thomas asked me to take through my tree.
To fix 'btime' virtualization we simply subtract the offset of the
time namespace's boottime from btime before printing the stats. Note
that since start_boottime of processes are seconds since boottime and
the boottime stamp is now shifted according to the time namespace's
offset, the offset of the time namespace also needs to be applied
before the process stats are given to userspace. This avoids that
processes shown by tools such as 'ps' appear as time travelers in the
corresponding time namespace.
Selftests are included to verify that btime virtualization in
/proc/stat works as expected"
* tag 'time-namespace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
namespace: make timens_on_fork() return nothing
selftests/timens: added selftest for /proc/stat btime
fs/proc: apply the time namespace offset to /proc/stat btime
timens: additional helper functions for boottime offset handling
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/array.c | 6 | ||||
| -rw-r--r-- | fs/proc/stat.c | 3 |
2 files changed, 7 insertions, 2 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c index 65ec2029fa80..277f654f289e 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -56,6 +56,7 @@ #include <linux/types.h> #include <linux/errno.h> #include <linux/time.h> +#include <linux/time_namespace.h> #include <linux/kernel.h> #include <linux/kernel_stat.h> #include <linux/tty.h> @@ -533,8 +534,9 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, priority = task_prio(task); nice = task_nice(task); - /* convert nsec -> ticks */ - start_time = nsec_to_clock_t(task->start_boottime); + /* apply timens offset for boottime and convert nsec -> ticks */ + start_time = + nsec_to_clock_t(timens_add_boottime_ns(task->start_boottime)); seq_put_decimal_ull(m, "", pid_nr_ns(pid, ns)); seq_puts(m, " ("); diff --git a/fs/proc/stat.c b/fs/proc/stat.c index 4695b6de3151..f25e8531fd27 100644 --- a/fs/proc/stat.c +++ b/fs/proc/stat.c @@ -10,6 +10,7 @@ #include <linux/seq_file.h> #include <linux/slab.h> #include <linux/time.h> +#include <linux/time_namespace.h> #include <linux/irqnr.h> #include <linux/sched/cputime.h> #include <linux/tick.h> @@ -118,6 +119,8 @@ static int show_stat(struct seq_file *p, void *v) irq = softirq = steal = 0; guest = guest_nice = 0; getboottime64(&boottime); + /* shift boot timestamp according to the timens offset */ + timens_sub_boottime(&boottime); for_each_possible_cpu(i) { struct kernel_cpustat kcpustat; |