Re: [kbuild-all] Re: [PATCH 3/3] proc: Remove the now unnecessary internal mount of proc

From: Li Zhijian
Date: Wed Mar 11 2020 - 22:04:17 EST




On 2/29/20 12:49 PM, Eric W. Biederman wrote:
kbuild test robot <lkp@xxxxxxxxx> writes:

Hi "Eric,

Thank you for the patch! Yet something to improve:
Dear kbuild robot,

Yep. You got it the wrong base. I will see about using --base
if I repost, or have another patchset that so clearly needs
to be applied on top of a non-default base.

Thank you for writing me how to do that.

Hi, Eric

May i know which tree/branch your patch is basing on ? this input might help 0day robot to pickup the candidate bases more intelligent.


Thanks
Zhijian


Eric


[auto build test ERROR on uml/linux-next]
[also build test ERROR on linux/master kees/for-next/pstore linus/master v5.6-rc3 next-20200228]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url: https://github.com/0day-ci/linux/commits/Eric-W-Biederman/proc-Actually-honor-the-mount-options/20200229-100926
base: https://git.kernel.org/pub/scm/linux/kernel/git/rw/uml.git linux-next
config: x86_64-defconfig (attached as .config)
compiler: gcc-7 (Debian 7.5.0-5) 7.5.0
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

fs/proc/base.c: In function 'proc_flush_task':
fs/proc/base.c:3217:33: error: 'struct pid_namespace' has no member named 'proc_mnt'; did you mean 'proc_self'?
proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
^~~~~~~~
proc_self

vim +3217 fs/proc/base.c

^1da177e4c3f41 Linus Torvalds 2005-04-16 3180
0895e91d60ef9b Randy Dunlap 2007-10-21 3181 /**
0895e91d60ef9b Randy Dunlap 2007-10-21 3182 * proc_flush_task - Remove dcache entries for @task from the /proc dcache.
0895e91d60ef9b Randy Dunlap 2007-10-21 3183 * @task: task that should be flushed.
0895e91d60ef9b Randy Dunlap 2007-10-21 3184 *
0895e91d60ef9b Randy Dunlap 2007-10-21 3185 * When flushing dentries from proc, one needs to flush them from global
60347f6716aa49 Pavel Emelyanov 2007-10-18 3186 * proc (proc_mnt) and from all the namespaces' procs this task was seen
0895e91d60ef9b Randy Dunlap 2007-10-21 3187 * in. This call is supposed to do all of this job.
0895e91d60ef9b Randy Dunlap 2007-10-21 3188 *
0895e91d60ef9b Randy Dunlap 2007-10-21 3189 * Looks in the dcache for
0895e91d60ef9b Randy Dunlap 2007-10-21 3190 * /proc/@pid
0895e91d60ef9b Randy Dunlap 2007-10-21 3191 * /proc/@tgid/task/@pid
0895e91d60ef9b Randy Dunlap 2007-10-21 3192 * if either directory is present flushes it and all of it'ts children
0895e91d60ef9b Randy Dunlap 2007-10-21 3193 * from the dcache.
0895e91d60ef9b Randy Dunlap 2007-10-21 3194 *
0895e91d60ef9b Randy Dunlap 2007-10-21 3195 * It is safe and reasonable to cache /proc entries for a task until
0895e91d60ef9b Randy Dunlap 2007-10-21 3196 * that task exits. After that they just clog up the dcache with
0895e91d60ef9b Randy Dunlap 2007-10-21 3197 * useless entries, possibly causing useful dcache entries to be
0895e91d60ef9b Randy Dunlap 2007-10-21 3198 * flushed instead. This routine is proved to flush those useless
0895e91d60ef9b Randy Dunlap 2007-10-21 3199 * dcache entries at process exit time.
0895e91d60ef9b Randy Dunlap 2007-10-21 3200 *
0895e91d60ef9b Randy Dunlap 2007-10-21 3201 * NOTE: This routine is just an optimization so it does not guarantee
0895e91d60ef9b Randy Dunlap 2007-10-21 3202 * that no dcache entries will exist at process exit time it
0895e91d60ef9b Randy Dunlap 2007-10-21 3203 * just makes it very unlikely that any will persist.
60347f6716aa49 Pavel Emelyanov 2007-10-18 3204 */
60347f6716aa49 Pavel Emelyanov 2007-10-18 3205
60347f6716aa49 Pavel Emelyanov 2007-10-18 3206 void proc_flush_task(struct task_struct *task)
60347f6716aa49 Pavel Emelyanov 2007-10-18 3207 {
9fcc2d15b14894 Eric W. Biederman 2007-11-14 3208 int i;
9b4d1cbef8f41a Oleg Nesterov 2009-09-22 3209 struct pid *pid, *tgid;
130f77ecb2e7d5 Pavel Emelyanov 2007-10-18 3210 struct upid *upid;
130f77ecb2e7d5 Pavel Emelyanov 2007-10-18 3211
130f77ecb2e7d5 Pavel Emelyanov 2007-10-18 3212 pid = task_pid(task);
130f77ecb2e7d5 Pavel Emelyanov 2007-10-18 3213 tgid = task_tgid(task);
9fcc2d15b14894 Eric W. Biederman 2007-11-14 3214
9fcc2d15b14894 Eric W. Biederman 2007-11-14 3215 for (i = 0; i <= pid->level; i++) {
130f77ecb2e7d5 Pavel Emelyanov 2007-10-18 3216 upid = &pid->numbers[i];
130f77ecb2e7d5 Pavel Emelyanov 2007-10-18 @3217 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
9b4d1cbef8f41a Oleg Nesterov 2009-09-22 3218 tgid->numbers[i].nr);
130f77ecb2e7d5 Pavel Emelyanov 2007-10-18 3219 }
60347f6716aa49 Pavel Emelyanov 2007-10-18 3220 }
60347f6716aa49 Pavel Emelyanov 2007-10-18 3221

:::::: The code at line 3217 was first introduced by commit
:::::: 130f77ecb2e7d5ac3e53e620f55e374f4a406b20 pid namespaces: make proc_flush_task() actually from entries from multiple namespaces

:::::: TO: Pavel Emelyanov <xemul@xxxxxxxxxx>
:::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxxxxxxxx>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
_______________________________________________
kbuild-all mailing list -- kbuild-all@xxxxxxxxxxxx
To unsubscribe send an email to kbuild-all-leave@xxxxxxxxxxxx