Messages in this thread | | | From | (Eric W. Biederman) | Date | Sun, 11 Dec 2011 23:30:21 -0800 | Subject | Re: [PATCH] fs, proc: Add start_data, end_data, start_brk members to /proc/$pid/stat v2 |
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Cyrill Gorcunov <gorcunov@gmail.com> writes:
> On Wed, Dec 07, 2011 at 10:33:08AM +0400, Cyrill Gorcunov wrote: >> >> No problem, I'll update (These segments are filled by binfmt handlers). >> > > This one should fit.
How extensively have you tested this. I remember a few other occasions where adding elements to a line in a proc file have resulted in breaking readers.
I expect it is much safer to add this to /proc/<pid>/status rather than /proc/<pid>/stat.
Eric
> > Cyrill > --- > From: Cyrill Gorcunov <gorcunov@openvz.org> > Subject: [PATCH] fs, proc: Add start_data, end_data, start_brk members to /proc/$pid/stat v4 > > These members are involved into calculation of program > data segment (which might be seen in /proc/<pid>/statm) > and into brk() call, so in a sake of restore we need > these entries to be set exactly to the same value the > process had at dumpimg time. > > While setting these entries back to a running task > is supposed to be done via prctl interface (which is > not addressed in this patch) the export of these values > are done via /proc/$pid/stat, which already have start_code, > end_code and start_stack entries. > > v2: > - Kees and Alexey pointed out that "1" hack is unnecessary, > so make it to have plain (mm && permitted) ? mm->member : 0 > form. > > v3: > - Andrew pointed that documentation update is missed. > Chagelog is updated as well. > > v4: > - Update proc.txt to address concerns from Kees and Kame. > > Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> > Acked-by: Serge Hallyn <serge.hallyn@canonical.com> > Reviewed-by: Kees Cook <keescook@chromium.org> > Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > CC: Alexey Dobriyan <adobriyan@gmail.com> > --- > Documentation/filesystems/proc.txt | 3 +++ > fs/proc/array.c | 7 +++++-- > 2 files changed, 8 insertions(+), 2 deletions(-) > > Index: linux-2.6.git/Documentation/filesystems/proc.txt > =================================================================== > --- linux-2.6.git.orig/Documentation/filesystems/proc.txt > +++ linux-2.6.git/Documentation/filesystems/proc.txt > @@ -305,6 +305,9 @@ Table 1-4: Contents of the stat files (a > blkio_ticks time spent waiting for block IO > gtime guest time of the task in jiffies > cgtime guest time of the task children in jiffies > + start_data address above which program data+bss is placed > + end_data address below which program data+bss is placed > + start_brk address above which program heap can be expaned with brk() call > .............................................................................. > > The /proc/PID/maps file containing the currently mapped memory regions and > Index: linux-2.6.git/fs/proc/array.c > =================================================================== > --- linux-2.6.git.orig/fs/proc/array.c > +++ linux-2.6.git/fs/proc/array.c > @@ -464,7 +464,7 @@ static int do_task_stat(struct seq_file > > seq_printf(m, "%d (%s) %c %d %d %d %d %d %u %lu \ > %lu %lu %lu %lu %lu %ld %ld %ld %ld %d 0 %llu %lu %ld %lu %lu %lu %lu %lu \ > -%lu %lu %lu %lu %lu %lu %lu %lu %d %d %u %u %llu %lu %ld\n", > +%lu %lu %lu %lu %lu %lu %lu %lu %d %d %u %u %llu %lu %ld %lu %lu %lu\n", > pid_nr_ns(pid, ns), > tcomm, > state, > @@ -511,7 +511,10 @@ static int do_task_stat(struct seq_file > task->policy, > (unsigned long long)delayacct_blkio_ticks(task), > cputime_to_clock_t(gtime), > - cputime_to_clock_t(cgtime)); > + cputime_to_clock_t(cgtime), > + (mm && permitted) ? mm->start_data : 0, > + (mm && permitted) ? mm->end_data : 0, > + (mm && permitted) ? mm->start_brk : 0); > if (mm) > mmput(mm); > return 0; > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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