On Sun, Mar 31, 2024 at 11:11:10PM +0800, kernel test robot wrote:
> kernel test robot noticed "UBSAN:shift-out-of-bounds_in_fs/proc/page.c" on:
>
> commit: 30e5296811312a13938b83956a55839ac1e3aa40 ("[PATCH 7/9] mm: Free up PG_slab")
Quite right. Spotted another one while I was at it. Not able to test
right now, but this should do the trick:
diff --git a/fs/proc/page.c b/fs/proc/page.c
index 5bc82828c6aa..55b01535eb22 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -175,6 +175,8 @@ u64 stable_page_flags(const struct page *page)
u |= 1 << KPF_OFFLINE;
if (PageTable(page))
u |= 1 << KPF_PGTABLE;
+ if (folio_test_slab(folio))
+ u |= 1 << KPF_SLAB;
#if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
u |= kpf_copy_bit(k, KPF_IDLE, PG_idle);
@@ -184,7 +186,6 @@ u64 stable_page_flags(const struct page *page)
#endif
u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
- u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
diff --git a/tools/cgroup/memcg_slabinfo.py b/tools/cgroup/memcg_slabinfo.py
index 1d3a90d93fe2..270c28a0d098 100644
--- a/tools/cgroup/memcg_slabinfo.py
+++ b/tools/cgroup/memcg_slabinfo.py
@@ -146,12 +146,11 @@ def detect_kernel_config():
def for_each_slab(prog):
- PGSlab = 1 << prog.constant('PG_slab')
- PGHead = 1 << prog.constant('PG_head')
+ PGSlab = ~prog.constant('PG_slab')
for page in for_each_page(prog):
try:
- if page.flags.value_() & PGSlab:
+ if page.page_type.value_() == PGSlab:
yield cast('struct slab *', page)
except FaultError:
pass
