On 2022/11/09 15:21, Lianbo Jiang wrote: > The ps/vm commands may print the bogus value of the %MEM and RSS, the > reason is that the counter of rss stat is updated in asynchronous manner > and may become negative, when the SPLIT_RSS_COUNTING is enabled in kernel. > > As a result, crash will read it from memory and convert from negative to > unsigned long integer, eventually it overflows and gets a big integer. For > example: > > crash> ps 1393 > PID PPID CPU TASK ST %MEM VSZ RSS COMM > 1393 1 24 ffff9584bb542100 RU 541298032135.9 4132 18014398509481908 enlinuxpc64 > ^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^ > > This is unexpected, crash needs to correct its value for this case. > > Signed-off-by: Lianbo Jiang <lijiang@xxxxxxxxxx> The patch looks good, applied. https://github.com/crash-utility/crash/commit/a158590f475c8d6d504b0c5e28b3cd91cfd47877 Thanks, Kazu > --- > memory.c | 23 ++++++++++++++++++----- > 1 file changed, 18 insertions(+), 5 deletions(-) > > diff --git a/memory.c b/memory.c > index 8724c4aa3d8a..9c15c1b745ef 100644 > --- a/memory.c > +++ b/memory.c > @@ -4714,18 +4714,29 @@ get_task_mem_usage(ulong task, struct task_mem_usage *tm) > * Latest kernels have mm_struct.mm_rss_stat[]. > */ > if (VALID_MEMBER(mm_struct_rss_stat)) { > - long anonpages, filepages; > + long anonpages, filepages, count; > > anonpages = tt->anonpages; > filepages = tt->filepages; > - rss += LONG(tt->mm_struct + > + count = LONG(tt->mm_struct + > OFFSET(mm_struct_rss_stat) + > OFFSET(mm_rss_stat_count) + > (filepages * sizeof(long))); > - rss += LONG(tt->mm_struct + > + > + /* > + * The counter is updated in asynchronous manner > + * and may become negative, see: > + * include/linux/mm.h: get_mm_counter() > + */ > + if (count > 0) > + rss += count; > + > + count = LONG(tt->mm_struct + > OFFSET(mm_struct_rss_stat) + > OFFSET(mm_rss_stat_count) + > (anonpages * sizeof(long))); > + if (count > 0) > + rss += count; > } > > /* Check whether SPLIT_RSS_COUNTING is enabled */ > @@ -4769,7 +4780,8 @@ get_task_mem_usage(ulong task, struct task_mem_usage *tm) > RETURN_ON_ERROR)) > continue; > > - rss_cache += sync_rss; > + if (sync_rss > 0) > + rss_cache += sync_rss; > > /* count 1 -> anonpages */ > if (!readmem(first->task + > @@ -4782,7 +4794,8 @@ get_task_mem_usage(ulong task, struct task_mem_usage *tm) > RETURN_ON_ERROR)) > continue; > > - rss_cache += sync_rss; > + if (sync_rss > 0) > + rss_cache += sync_rss; > > if (first == last) > break; -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/crash-utility Contribution Guidelines: https://github.com/crash-utility/crash/wiki
