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Shutemov" , Andrew Morton , David Hildenbrand Cc: lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, hannes@cmpxchg.org, shakeel.butt@linux.dev, muchun.song@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Konstantin Khlebnikov References: <20250604095111.533783-1-kirill.shutemov@linux.intel.com> Content-Language: en-US From: Randy Dunlap In-Reply-To: <20250604095111.533783-1-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Stat-Signature: dmsssd4atomrfr788d9hzf771reu6rnd X-Rspamd-Queue-Id: 8E4BA140017 X-Rspamd-Server: rspam11 X-HE-Tag: 1749051616-792536 X-HE-Meta: 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 ca4AT01Z d0vOeAEdQpJPbDxIDcUtn9nfti2YLP0qkU3aGmuz8cOVXikTLE0Tj8a937Sq1S2V1ih73mcwJeJnNRlz7iod+aQ7BzQsu+iTG5rV/fgaOzr1xkw/sGEKDqMlZO0TdE0ua/T2LzcaiARjzzBY4bNVi8TY1//nflMzQTJWRwFDlQpXiSE00KNzddhU0n2YjX0VwUV2RTs08lJJYMGaxhJTDMuZxC9l6dGmu0gGVRsdX5j1Wks+OOE2BwpFmVqve/kn2ezPZfmKrl4pfROlcTiv2PAdSp1NMpd/55iLpNnoWeAR8cZuj6GvRLegQEpn80z/a5TLF2Tpp7Vgm6/jEQ/786TKF4CfJWAy5MlxNf1+9uu5/mTVOiIy8avS7Skk6ASMDf6qOKhaGkxFLPbzmOpnl8PiLLcwjIIfP7MJd72MooYpV+Pw= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 6/4/25 2:51 AM, Kirill A. Shutemov wrote: > When compiling with MEMCG enabled but VM_EVENT_COUNTERS disabled, > BUILD_BUG_ON() is triggered in vmstat_start because the vmstat_text > array is larger than NR_VMSTAT_ITEMS. > > This issue arises because some elements of the vmstat_text array are > present when either MEMCG or VM_EVENT_COUNTERS is enabled, but > NR_VMSTAT_ITEMS only accounts for these elements if VM_EVENT_COUNTERS is > enabled. > > The recent change in the BUILD_BUG_ON() check made it more strict, > disallowing extra elements in the array, which revealed the issue. > > Instead of adjusting the NR_VMSTAT_ITEMS definition to account for > MEMCG, make MEMCG select VM_EVENT_COUNTERS. VM_EVENT_COUNTERS is > enabled in most configurations anyway. > > There is no need to backport this fix to stable trees. Without the > strict BUILD_BUG_ON(), the issue is not harmful. The elements in > question would only be read by the memcg code, not by /proc/vmstat. > > Signed-off-by: Kirill A. Shutemov > Reported-by: Randy Dunlap > Fixes: ebc5d83d0443 ("mm/memcontrol: use vmstat names for printing statistics") > Cc: Konstantin Khlebnikov Tested-by: Randy Dunlap Acked-by: Randy Dunlap Thanks. > --- > include/linux/vmstat.h | 4 ++-- > init/Kconfig | 1 + > mm/vmstat.c | 4 ++-- > 3 files changed, 5 insertions(+), 4 deletions(-) > > diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h > index b2ccb6845595..c287998908bf 100644 > --- a/include/linux/vmstat.h > +++ b/include/linux/vmstat.h > @@ -507,7 +507,7 @@ static inline const char *lru_list_name(enum lru_list lru) > return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_" > } > > -#if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG) > +#if defined(CONFIG_VM_EVENT_COUNTERS) > static inline const char *vm_event_name(enum vm_event_item item) > { > return vmstat_text[NR_VM_ZONE_STAT_ITEMS + > @@ -516,7 +516,7 @@ static inline const char *vm_event_name(enum vm_event_item item) > NR_VM_STAT_ITEMS + > item]; > } > -#endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */ > +#endif /* CONFIG_VM_EVENT_COUNTERS */ > > #ifdef CONFIG_MEMCG > > diff --git a/init/Kconfig b/init/Kconfig > index ab83abe0fd9d..dd332cac6036 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -989,6 +989,7 @@ config MEMCG > select PAGE_COUNTER > select EVENTFD > select SLAB_OBJ_EXT > + select VM_EVENT_COUNTERS > help > Provides control over the memory footprint of tasks in a cgroup. > > diff --git a/mm/vmstat.c b/mm/vmstat.c > index 27dc37168cfd..c3114b8826e4 100644 > --- a/mm/vmstat.c > +++ b/mm/vmstat.c > @@ -1301,7 +1301,7 @@ const char * const vmstat_text[] = { > [I(NR_MEMMAP_BOOT_PAGES)] = "nr_memmap_boot_pages", > #undef I > > -#if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG) > +#if defined(CONFIG_VM_EVENT_COUNTERS) > /* enum vm_event_item counters */ > #define I(x) (NR_VM_ZONE_STAT_ITEMS + NR_VM_NUMA_EVENT_ITEMS + \ > NR_VM_NODE_STAT_ITEMS + NR_VM_STAT_ITEMS + x) > @@ -1498,7 +1498,7 @@ const char * const vmstat_text[] = { > #endif > #endif > #undef I > -#endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */ > +#endif /* CONFIG_VM_EVENT_COUNTERS */ > }; > #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */ > -- ~Randy