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(a)redhat.com&gt; --- 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; -- 2.37.1