From nobody Sun Feb 8 05:23:15 2026 Received: from smtpout.efficios.com (smtpout.efficios.com [158.69.130.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C295D2765ED; Sun, 21 Dec 2025 23:29:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=158.69.130.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766359794; cv=none; b=TMkIAX9NnGGKjid+hdEpnpP50A85ydKkhaluROJwSkrccso7RIYEwBmyHfN9s3zqnTOFSdFkAAYuYc37kp+vjns/8eihm2deDDnQh2kMSBbMYQ3lDaINaQk8kAQ5g/iGaxxtqQwYT3kPE/ozF9QzE7ACuhFxu2HeN8Kai+RVuNo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766359794; c=relaxed/simple; bh=Ogk/dngzVOmKb1C80LeAS2BE01H8MPAYx/arFDCFiok=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=AW3UNh9FfB1+IDi9Lhg1jRRd9MFDnTAx/tjXW7CJoVvC9pH7mhwQwqtROJEjJKCxuk5BuPkhaKWHfs7BCRowl1/O/2NjWJ1Qp8XL9RCmXivnREK0vlMzHiTqEuh1UT5skQqqOiVeAWo1gDfkSJLi0Y71oo+H9D9D08C45uZuGK0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b=YNn1W6LL; arc=none smtp.client-ip=158.69.130.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="YNn1W6LL" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=smtpout1; t=1766359786; bh=Mq4W7sDg/Agh00nn/sSC9HgKzw4XSoLV+yJE0vShXuM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YNn1W6LLVQr7r81fgVrE3iNKt1NbFU1kaCmp41f1sr3h67Na+MJcI6xiUNS/yf9zp VkeHEXt1ZmtVZVS2CEuqTCeQH48lrGG8jrtI8lnMVc20Co8UZho3SC4D373TD/SJrX A/fasWo/5zs6dywhjCNWiinaPJKgo59T75k91mbbLOfwb/xcnDeF3R0G+AtwX8c9qY 02HNkcn5w0M++hHJLUyABFY0rNbaqp+c0jXbKUANKkMPg+58+jQwIG7kAy603gQg8Z CdRlGvUD2nW9jaO4APDzwk68vlYWVextGyqAZD/yG8PR5lRk8Bz5eB6n8hDE8tHr1n 4sgCmvYJbvonA== Received: from thinkos.internal.efficios.com (unknown [IPv6:2606:6d00:100:4000:6450:b8a1:16cf:5ecf]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4dZHYQ0bfbzd8N; Sun, 21 Dec 2025 18:29:46 -0500 (EST) From: Mathieu Desnoyers To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Mark Brown , linux-mm@kvack.org, Thomas Gleixner , stable@vger.kernel.org Subject: [PATCH v1 1/5] mm: Add missing static initializer for init_mm::mm_cid.lock Date: Sun, 21 Dec 2025 18:29:22 -0500 Message-Id: <20251221232926.450602-2-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20251221232926.450602-1-mathieu.desnoyers@efficios.com> References: <20251221232926.450602-1-mathieu.desnoyers@efficios.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Initialize the mm_cid.lock struct member of init_mm. Fixes: 8cea569ca785 ("sched/mmcid: Use proper data structures") Signed-off-by: Mathieu Desnoyers Cc: Andrew Morton Cc: Thomas Gleixner Cc: stable@vger.kernel.org Cc: linux-mm@kvack.org --- mm/init-mm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/init-mm.c b/mm/init-mm.c index 4600e7605cab..a514f8ce47e3 100644 --- a/mm/init-mm.c +++ b/mm/init-mm.c @@ -44,6 +44,9 @@ struct mm_struct init_mm =3D { .mm_lock_seq =3D SEQCNT_ZERO(init_mm.mm_lock_seq), #endif .user_ns =3D &init_user_ns, +#ifdef CONFIG_SCHED_MM_CID + .mm_cid.lock =3D __RAW_SPIN_LOCK_UNLOCKED(init_mm.mm_cid.lock), +#endif .cpu_bitmap =3D CPU_BITS_NONE, INIT_MM_CONTEXT(init_mm) }; --=20 2.39.5 From nobody Sun Feb 8 05:23:15 2026 Received: from smtpout.efficios.com (smtpout.efficios.com [158.69.130.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE614262FFF for ; Sun, 21 Dec 2025 23:29:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=158.69.130.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766359794; cv=none; b=ZKFmHu2J5xRpyNE73ymkT7xyg7S1LeKOxZZXP9Byal9KShzFfF73uJfdCOrJ3lxvNV7HeXAMblyyHNEnY4idx12HZA0kVBJIoWETkSdXm+h8SiyDfW1fjorybyEbjk+/9xwL4XGqdY3yhAkqpB4NavVqkJqNtV5gaUHFMv/M9vw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766359794; c=relaxed/simple; bh=97Bba2IVpIiZDuW5qVn6n2hCZ28cMWY6G+U8FCejAAY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=DJOQMEIf+Z9Nq+fDEnqgQ99aao2VeLfwqZzdwIioEi+1Clen60Db4fSm0nW6oVkYzKwWKTuUMEaAU9F9N/se80xz7Ru4PVppltjhOYIFtGVP1pVqOZH4Nhnd2sDU1XboQhlvTkGoVETpCudtFrYHQuDo2LIQEe+wdsVVWaPPH4Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b=cnc5f6qK; arc=none smtp.client-ip=158.69.130.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="cnc5f6qK" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=smtpout1; t=1766359786; bh=bggeet/K7f/LykaY9i5CXV4NsffNnOWo1S/CrVN1N6M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cnc5f6qKjNWTp5CYe3FtMEqXjaEtwaL5KnWMM06i0PVH+WPEPspj9cYDBTvZjbAPl LzhO4ykoMqjew6uDzSWYAvjT8sxTLGeysoAT8/VuHK8OtbbJhFcglGCLLqg6OM/ZkN tvdwIJRnC5/3tsUuE7EGMICCVIIMcQ9G/qN7IPcE3YGzNsCiCPLx2qF4E8Udx0p2A+ PweF6eTwZbqfCL1RTbXB3X3iGZMNYbMtwpkC5bWW1IvClcXM2Hm6U9NyHK/jREt4e+ up7IXK3+ZoobM0LaQmmelFCWFxr5h46TnAOOrWVS5lDZTwNHt8mgMKVRphjb1MvLTe JYWkOBKaZF2aA== Received: from thinkos.internal.efficios.com (unknown [IPv6:2606:6d00:100:4000:6450:b8a1:16cf:5ecf]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4dZHYQ1VJHzdCd; Sun, 21 Dec 2025 18:29:46 -0500 (EST) From: Mathieu Desnoyers To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Mark Brown , linux-mm@kvack.org Subject: [PATCH v1 2/5] mm: Rename cpu_bitmap field to flexible_array Date: Sun, 21 Dec 2025 18:29:23 -0500 Message-Id: <20251221232926.450602-3-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20251221232926.450602-1-mathieu.desnoyers@efficios.com> References: <20251221232926.450602-1-mathieu.desnoyers@efficios.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The cpu_bitmap flexible array now contains more than just the cpu_bitmap. In preparation for changing the static mm_struct definitions to cover for the additional space required, change the cpu_bitmap type from "unsigned long" to "char", require an unsigned long alignment of the flexible array, and rename the field from "cpu_bitmap" to "flexible_array". Introduce the MM_STRUCT_FLEXIBLE_ARRAY_INIT macro to statically initialize the flexible array. This covers the init_mm and efi_mm static definitions. This is a preparation step for fixing the missing mm_cid size for static mm_struct definitions. Signed-off-by: Mathieu Desnoyers Cc: Andrew Morton Cc: Mark Brown Cc: linux-mm@kvack.org --- drivers/firmware/efi/efi.c | 2 +- include/linux/mm.h | 2 +- include/linux/mm_types.h | 13 +++++++++---- mm/init-mm.c | 2 +- 4 files changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index a9070d00b833..3f5c2ae50024 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -73,10 +73,10 @@ struct mm_struct efi_mm =3D { MMAP_LOCK_INITIALIZER(efi_mm) .page_table_lock =3D __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock), .mmlist =3D LIST_HEAD_INIT(efi_mm.mmlist), - .cpu_bitmap =3D { [BITS_TO_LONGS(NR_CPUS)] =3D 0}, #ifdef CONFIG_SCHED_MM_CID .mm_cid.lock =3D __RAW_SPIN_LOCK_UNLOCKED(efi_mm.mm_cid.lock), #endif + .flexible_array =3D MM_STRUCT_FLEXIBLE_ARRAY_INIT, }; =20 struct workqueue_struct *efi_rts_wq; diff --git a/include/linux/mm.h b/include/linux/mm.h index 890dab720f75..8d9e3239d2cc 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2853,7 +2853,7 @@ static inline struct percpu_counter_tree_level_item *= get_rss_stat_items(struct m { unsigned long ptr =3D (unsigned long)mm; =20 - ptr +=3D offsetof(struct mm_struct, cpu_bitmap); + ptr +=3D offsetof(struct mm_struct, flexible_array); /* Skip cpu_bitmap */ ptr +=3D cpumask_size(); /* Skip mm_cidmask */ diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index a6287d07efb7..1531df8cda52 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1329,7 +1329,7 @@ struct mm_struct { * The mm_cpumask needs to be at the end of mm_struct, because it * is dynamically sized based on nr_cpu_ids. */ - unsigned long cpu_bitmap[]; + char flexible_array[] __aligned(__alignof__(unsigned long)); }; =20 /* Copy value to the first system word of mm flags, non-atomically. */ @@ -1366,19 +1366,24 @@ static inline void __mm_flags_set_mask_bits_word(st= ruct mm_struct *mm, MT_FLAGS_USE_RCU) extern struct mm_struct init_mm; =20 +#define MM_STRUCT_FLEXIBLE_ARRAY_INIT \ +{ \ + [0 ... sizeof(cpumask_t)-1] =3D 0 \ +} + /* Pointer magic because the dynamic array size confuses some compilers. */ static inline void mm_init_cpumask(struct mm_struct *mm) { unsigned long cpu_bitmap =3D (unsigned long)mm; =20 - cpu_bitmap +=3D offsetof(struct mm_struct, cpu_bitmap); + cpu_bitmap +=3D offsetof(struct mm_struct, flexible_array); cpumask_clear((struct cpumask *)cpu_bitmap); } =20 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ static inline cpumask_t *mm_cpumask(struct mm_struct *mm) { - return (struct cpumask *)&mm->cpu_bitmap; + return (struct cpumask *)&mm->flexible_array; } =20 #ifdef CONFIG_LRU_GEN @@ -1469,7 +1474,7 @@ static inline cpumask_t *mm_cpus_allowed(struct mm_st= ruct *mm) { unsigned long bitmap =3D (unsigned long)mm; =20 - bitmap +=3D offsetof(struct mm_struct, cpu_bitmap); + bitmap +=3D offsetof(struct mm_struct, flexible_array); /* Skip cpu_bitmap */ bitmap +=3D cpumask_size(); return (struct cpumask *)bitmap; diff --git a/mm/init-mm.c b/mm/init-mm.c index a514f8ce47e3..c5556bb9d5f0 100644 --- a/mm/init-mm.c +++ b/mm/init-mm.c @@ -47,7 +47,7 @@ struct mm_struct init_mm =3D { #ifdef CONFIG_SCHED_MM_CID .mm_cid.lock =3D __RAW_SPIN_LOCK_UNLOCKED(init_mm.mm_cid.lock), #endif - .cpu_bitmap =3D CPU_BITS_NONE, + .flexible_array =3D MM_STRUCT_FLEXIBLE_ARRAY_INIT, INIT_MM_CONTEXT(init_mm) }; 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Sun, 21 Dec 2025 18:29:46 -0500 (EST) From: Mathieu Desnoyers To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Mark Brown , linux-mm@kvack.org, Thomas Gleixner , stable@vger.kernel.org Subject: [PATCH v1 3/5] mm: Take into account mm_cid size for mm_struct static definitions Date: Sun, 21 Dec 2025 18:29:24 -0500 Message-Id: <20251221232926.450602-4-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20251221232926.450602-1-mathieu.desnoyers@efficios.com> References: <20251221232926.450602-1-mathieu.desnoyers@efficios.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Both init_mm and efi_mm static definitions need to make room for the 2 mm_cid cpumasks. This fixes possible out-of-bounds accesses to init_mm and efi_mm. Fixes: af7f588d8f73 ("sched: Introduce per-memory-map concurrency ID") Signed-off-by: Mathieu Desnoyers Cc: Andrew Morton Cc: Thomas Gleixner Cc: Mark Brown Cc: stable@vger.kernel.org Cc: linux-mm@kvack.org --- include/linux/mm_types.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 1531df8cda52..aefa64db3499 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1368,7 +1368,7 @@ extern struct mm_struct init_mm; =20 #define MM_STRUCT_FLEXIBLE_ARRAY_INIT \ { \ - [0 ... sizeof(cpumask_t)-1] =3D 0 \ + [0 ... sizeof(cpumask_t) + MM_CID_STATIC_SIZE - 1] =3D 0 \ } =20 /* Pointer magic because the dynamic array size confuses some compilers. */ @@ -1500,7 +1500,7 @@ static inline int mm_alloc_cid_noprof(struct mm_struc= t *mm, struct task_struct * mm_init_cid(mm, p); return 0; } -#define mm_alloc_cid(...) alloc_hooks(mm_alloc_cid_noprof(__VA_ARGS__)) +# define mm_alloc_cid(...) alloc_hooks(mm_alloc_cid_noprof(__VA_ARGS__)) =20 static inline void mm_destroy_cid(struct mm_struct *mm) { @@ -1514,6 +1514,8 @@ static inline unsigned int mm_cid_size(void) return cpumask_size() + bitmap_size(num_possible_cpus()); } =20 +/* Use NR_CPUS as worse case for static allocation. */ +# define MM_CID_STATIC_SIZE (2 * sizeof(cpumask_t)) #else /* CONFIG_SCHED_MM_CID */ static inline void mm_init_cid(struct mm_struct *mm, struct task_struct *p= ) { } static inline int mm_alloc_cid(struct mm_struct *mm, struct task_struct *p= ) { return 0; } @@ -1522,6 +1524,7 @@ static inline unsigned int mm_cid_size(void) { return 0; } +# define MM_CID_STATIC_SIZE 0 #endif /* CONFIG_SCHED_MM_CID */ =20 struct mmu_gather; --=20 2.39.5 From nobody Sun Feb 8 05:23:15 2026 Received: from smtpout.efficios.com (smtpout.efficios.com [158.69.130.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C13DA274FD0 for ; Sun, 21 Dec 2025 23:29:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=158.69.130.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766359795; cv=none; 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spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="OOTm0N9Q" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=smtpout1; t=1766359786; bh=v7Y9Jpp91tliTBnX3yTO+/rJorulikI8K3gXOhRJ/5I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OOTm0N9QKa8v9m4VWiu2o+fqq181KmnELB4psxxqAEB0zXvuFUJZZxE7KUFKys2pd h/bjuWvBGwIRsw6ca+9e4wPohsv9V7yQdW5dzufgdSzzCH/L0mHE9PVJX6Bpyte10e 713DTDSOs8Np0TN/AkGttfNNpC+v60uU0oD/9mb7uveuup16nvMMhjniwyGtb9df6q ucdPJDnzKZpBbX+BrdCHdUub5uMr1/uatB1vdpag54wmnalERafvRUVVFHT/q1plez 3T6CsujturCb8OwUzGZbDBqpLClrB3ynH6chxMKkPbXoB61BV4UJIAHcRvrP1+eGPF aD8rKkZeUpxjg== Received: from thinkos.internal.efficios.com (unknown [IPv6:2606:6d00:100:4000:6450:b8a1:16cf:5ecf]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4dZHYQ3CMRzdCf; Sun, 21 Dec 2025 18:29:46 -0500 (EST) From: Mathieu Desnoyers To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Mark Brown , linux-mm@kvack.org Subject: [PATCH v1 4/5] mm: Take into account hierarchical percpu tree items for static mm_struct definitions Date: Sun, 21 Dec 2025 18:29:25 -0500 Message-Id: <20251221232926.450602-5-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20251221232926.450602-1-mathieu.desnoyers@efficios.com> References: <20251221232926.450602-1-mathieu.desnoyers@efficios.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Both init_mm and efi_mm static definitions need to make room for the hierarchical percpu counters items. This fixes possible out-of-bounds accesses to init_mm and efi_mm. Signed-off-by: Mathieu Desnoyers Cc: Andrew Morton Cc: Mark Brown Cc: linux-mm@kvack.org --- include/linux/mm_types.h | 6 ++-- include/linux/percpu_counter_tree.h | 51 +++++++++++++++++++++++++++++ 2 files changed, 54 insertions(+), 3 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index aefa64db3499..234374c46b71 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1366,9 +1366,9 @@ static inline void __mm_flags_set_mask_bits_word(stru= ct mm_struct *mm, MT_FLAGS_USE_RCU) extern struct mm_struct init_mm; =20 -#define MM_STRUCT_FLEXIBLE_ARRAY_INIT \ -{ \ - [0 ... sizeof(cpumask_t) + MM_CID_STATIC_SIZE - 1] =3D 0 \ +#define MM_STRUCT_FLEXIBLE_ARRAY_INIT \ +{ \ + [0 ... sizeof(cpumask_t) + MM_CID_STATIC_SIZE + PERCPU_COUNTER_TREE_ITEMS= _STATIC_SIZE - 1] =3D 0 \ } =20 /* Pointer magic because the dynamic array size confuses some compilers. */ diff --git a/include/linux/percpu_counter_tree.h b/include/linux/percpu_cou= nter_tree.h index 0daf09e08111..2e8b1ce5cd13 100644 --- a/include/linux/percpu_counter_tree.h +++ b/include/linux/percpu_counter_tree.h @@ -10,6 +10,52 @@ =20 #ifdef CONFIG_SMP =20 +#if NR_CPUS =3D=3D (1U << 0) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 0 +#elif NR_CPUS <=3D (1U << 1) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 1 +#elif NR_CPUS <=3D (1U << 2) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 3 +#elif NR_CPUS <=3D (1U << 3) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 7 +#elif NR_CPUS <=3D (1U << 4) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 7 +#elif NR_CPUS <=3D (1U << 5) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 11 +#elif NR_CPUS <=3D (1U << 6) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 21 +#elif NR_CPUS <=3D (1U << 7) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 21 +#elif NR_CPUS <=3D (1U << 8) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 37 +#elif NR_CPUS <=3D (1U << 9) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 73 +#elif NR_CPUS <=3D (1U << 10) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 149 +#elif NR_CPUS <=3D (1U << 11) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 293 +#elif NR_CPUS <=3D (1U << 12) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 585 +#elif NR_CPUS <=3D (1U << 13) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 1173 +#elif NR_CPUS <=3D (1U << 14) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 2341 +#elif NR_CPUS <=3D (1U << 15) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 4681 +#elif NR_CPUS <=3D (1U << 16) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 4681 +#elif NR_CPUS <=3D (1U << 17) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 8777 +#elif NR_CPUS <=3D (1U << 18) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 17481 +#elif NR_CPUS <=3D (1U << 19) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 34953 +#elif NR_CPUS <=3D (1U << 20) +# define PERCPU_COUNTER_TREE_STATIC_NR_ITEMS 69905 +#else +# error "Unsupported number of CPUs." +#endif + struct percpu_counter_tree_level_item { atomic_t count; /* * Count the number of carry fort this tree item. @@ -18,6 +64,9 @@ struct percpu_counter_tree_level_item { */ } ____cacheline_aligned_in_smp; =20 +#define PERCPU_COUNTER_TREE_ITEMS_STATIC_SIZE \ + (PERCPU_COUNTER_TREE_STATIC_NR_ITEMS * sizeof(struct percpu_counter_tree_= level_item)) + struct percpu_counter_tree { /* Fast-path fields. */ unsigned int __percpu *level0; /* Pointer to per-CPU split counters (tree= level 0). */ @@ -92,6 +141,8 @@ int percpu_counter_tree_approximate_sum(struct percpu_co= unter_tree *counter) =20 #else /* !CONFIG_SMP */ =20 +#define PERCPU_COUNTER_TREE_ITEMS_STATIC_SIZE 0 + struct percpu_counter_tree_level_item; =20 struct percpu_counter_tree { --=20 2.39.5 From nobody Sun Feb 8 05:23:15 2026 Received: from smtpout.efficios.com (smtpout.efficios.com [158.69.130.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 567BB27E05A for ; Sun, 21 Dec 2025 23:29:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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charset="utf-8" When we hit acct_account_cputime within a irq handler over a kthread that happens to use a userspace mm, we end up summing up the mm's RSS into the tsk acct_rss_mem1, which eventually decays. I don't see a good rationale behind tracking the mm's rss in that way when a kthread use a userspace mm temporarily through use_mm. It causes issues with init_mm and efi_mm which only partially initialize their mm_struct. Skip all kernel threads in acct_account_cputime(), not just those that happen to have a NULL mm. Signed-off-by: Mathieu Desnoyers Cc: Andrew Morton Cc: Mark Brown Cc: linux-mm@kvack.org --- kernel/tsacct.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/tsacct.c b/kernel/tsacct.c index 6ea2f6363b90..3ef149b1245d 100644 --- a/kernel/tsacct.c +++ b/kernel/tsacct.c @@ -125,7 +125,7 @@ static void __acct_update_integrals(struct task_struct = *tsk, { u64 time, delta; =20 - if (!likely(tsk->mm)) + if (!tsk->mm || (tsk->flags & PF_KTHREAD)) return; =20 time =3D stime + utime; --=20 2.39.5