lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20231024134637.3120277-39-surenb@google.com>
Date:   Tue, 24 Oct 2023 06:46:35 -0700
From:   Suren Baghdasaryan <surenb@...gle.com>
To:     akpm@...ux-foundation.org
Cc:     kent.overstreet@...ux.dev, mhocko@...e.com, vbabka@...e.cz,
        hannes@...xchg.org, roman.gushchin@...ux.dev, mgorman@...e.de,
        dave@...olabs.net, willy@...radead.org, liam.howlett@...cle.com,
        corbet@....net, void@...ifault.com, peterz@...radead.org,
        juri.lelli@...hat.com, ldufour@...ux.ibm.com,
        catalin.marinas@....com, will@...nel.org, arnd@...db.de,
        tglx@...utronix.de, mingo@...hat.com, dave.hansen@...ux.intel.com,
        x86@...nel.org, peterx@...hat.com, david@...hat.com,
        axboe@...nel.dk, mcgrof@...nel.org, masahiroy@...nel.org,
        nathan@...nel.org, dennis@...nel.org, tj@...nel.org,
        muchun.song@...ux.dev, rppt@...nel.org, paulmck@...nel.org,
        pasha.tatashin@...een.com, yosryahmed@...gle.com,
        yuzhao@...gle.com, dhowells@...hat.com, hughd@...gle.com,
        andreyknvl@...il.com, keescook@...omium.org,
        ndesaulniers@...gle.com, vvvvvv@...gle.com,
        gregkh@...uxfoundation.org, ebiggers@...gle.com, ytcoode@...il.com,
        vincent.guittot@...aro.org, dietmar.eggemann@....com,
        rostedt@...dmis.org, bsegall@...gle.com, bristot@...hat.com,
        vschneid@...hat.com, cl@...ux.com, penberg@...nel.org,
        iamjoonsoo.kim@....com, 42.hyeyoo@...il.com, glider@...gle.com,
        elver@...gle.com, dvyukov@...gle.com, shakeelb@...gle.com,
        songmuchun@...edance.com, jbaron@...mai.com, rientjes@...gle.com,
        minchan@...gle.com, kaleshsingh@...gle.com, surenb@...gle.com,
        kernel-team@...roid.com, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, iommu@...ts.linux.dev,
        linux-arch@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-mm@...ck.org, linux-modules@...r.kernel.org,
        kasan-dev@...glegroups.com, cgroups@...r.kernel.org
Subject: [PATCH v2 38/39] codetag: debug: introduce OBJEXTS_ALLOC_FAIL to mark
 failed slab_ext allocations

If slabobj_ext vector allocation for a slab object fails and later on it
succeeds for another object in the same slab, the slabobj_ext for the
original object will be NULL and will be flagged in case when
CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled.
Mark failed slabobj_ext vector allocations using a new objext_flags flag
stored in the lower bits of slab->obj_exts. When new allocation succeeds
it marks all tag references in the same slabobj_ext vector as empty to
avoid warnings implemented by CONFIG_MEM_ALLOC_PROFILING_DEBUG checks.

Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
---
 include/linux/memcontrol.h |  4 +++-
 mm/slab.h                  | 25 +++++++++++++++++++++++++
 mm/slab_common.c           | 22 +++++++++++++++-------
 3 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 853a24b5f713..6b680ca424e3 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -363,8 +363,10 @@ enum page_memcg_data_flags {
 #endif /* CONFIG_MEMCG */
 
 enum objext_flags {
+	/* slabobj_ext vector failed to allocate */
+	OBJEXTS_ALLOC_FAIL = __FIRST_OBJEXT_FLAG,
 	/* the next bit after the last actual flag */
-	__NR_OBJEXTS_FLAGS  = __FIRST_OBJEXT_FLAG,
+	__NR_OBJEXTS_FLAGS  = (__FIRST_OBJEXT_FLAG << 1),
 };
 
 #define OBJEXTS_FLAGS_MASK (__NR_OBJEXTS_FLAGS - 1)
diff --git a/mm/slab.h b/mm/slab.h
index 45216bad34b8..1736268892e6 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -474,9 +474,34 @@ static inline void mark_objexts_empty(struct slabobj_ext *obj_exts)
 	}
 }
 
+static inline void mark_failed_objexts_alloc(struct slab *slab)
+{
+	slab->obj_exts = OBJEXTS_ALLOC_FAIL;
+}
+
+static inline void handle_failed_objexts_alloc(unsigned long obj_exts,
+			struct slabobj_ext *vec, unsigned int objects)
+{
+	/*
+	 * If vector previously failed to allocate then we have live
+	 * objects with no tag reference. Mark all references in this
+	 * vector as empty to avoid warnings later on.
+	 */
+	if (obj_exts & OBJEXTS_ALLOC_FAIL) {
+		unsigned int i;
+
+		for (i = 0; i < objects; i++)
+			set_codetag_empty(&vec[i].ref);
+	}
+}
+
+
 #else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
 
 static inline void mark_objexts_empty(struct slabobj_ext *obj_exts) {}
+static inline void mark_failed_objexts_alloc(struct slab *slab) {}
+static inline void handle_failed_objexts_alloc(unsigned long obj_exts,
+			struct slabobj_ext *vec, unsigned int objects) {}
 
 #endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
 
diff --git a/mm/slab_common.c b/mm/slab_common.c
index db2cd7afc353..cea73314f919 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -218,29 +218,37 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
 			gfp_t gfp, bool new_slab)
 {
 	unsigned int objects = objs_per_slab(s, slab);
-	unsigned long obj_exts;
-	void *vec;
+	unsigned long new_exts;
+	unsigned long old_exts;
+	struct slabobj_ext *vec;
 
 	gfp &= ~OBJCGS_CLEAR_MASK;
 	/* Prevent recursive extension vector allocation */
 	gfp |= __GFP_NO_OBJ_EXT;
 	vec = kcalloc_node(objects, sizeof(struct slabobj_ext), gfp,
 			   slab_nid(slab));
-	if (!vec)
+	if (!vec) {
+		/* Mark vectors which failed to allocate */
+		if (new_slab)
+			mark_failed_objexts_alloc(slab);
+
 		return -ENOMEM;
+	}
 
-	obj_exts = (unsigned long)vec;
+	new_exts = (unsigned long)vec;
 #ifdef CONFIG_MEMCG
-	obj_exts |= MEMCG_DATA_OBJEXTS;
+	new_exts |= MEMCG_DATA_OBJEXTS;
 #endif
+	old_exts = slab->obj_exts;
+	handle_failed_objexts_alloc(old_exts, vec, objects);
 	if (new_slab) {
 		/*
 		 * If the slab is brand new and nobody can yet access its
 		 * obj_exts, no synchronization is required and obj_exts can
 		 * be simply assigned.
 		 */
-		slab->obj_exts = obj_exts;
-	} else if (cmpxchg(&slab->obj_exts, 0, obj_exts)) {
+		slab->obj_exts = new_exts;
+	} else if (cmpxchg(&slab->obj_exts, old_exts, new_exts) != old_exts) {
 		/*
 		 * If the slab is already in use, somebody can allocate and
 		 * assign slabobj_exts in parallel. In this case the existing
-- 
2.42.0.758.gaed0368e0e-goog

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ