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AJvYcCXQUe56NDBccd0ilMg/lXYXdoCFWmArk6cmcQ/omXkSS/R57i/vPYOO6fVS3ZX66D2Yv5jDcXE7iB2lQrU=@vger.kernel.org X-Gm-Message-State: AOJu0Yyur+RWjRkecKle8QJW7eWTskJIqlCQQcWIfrqQGF4ZMZXvGayn YX3eV4lpJpR9xX6G2Z7SyDXiWKUB9O91jTJFPKD/4+nIbNd9YM+ZY8nxCy/aqzbTXzN0g3dz5Av QBDR0Cw== X-Google-Smtp-Source: AGHT+IHE0hHtw1Xg0PUR8LXW1OvNYnxaIuDbWWkKp1lBoeFA09FI3YbrJczkDR7Cbe5a+Wuqw/7opjyJj9c= X-Received: from pjqs17.prod.google.com ([2002:a17:90a:ad91:b0:31e:eff2:4575]) (user=surenb job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:f64a:b0:240:3f39:2c73 with SMTP id d9443c01a7336-242c19ac4f0mr49253725ad.0.1754666937755; Fri, 08 Aug 2025 08:28:57 -0700 (PDT) Date: Fri, 8 Aug 2025 08:28:48 -0700 In-Reply-To: <20250808152850.2580887-1-surenb@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250808152850.2580887-1-surenb@google.com> X-Mailer: git-send-email 2.50.1.703.g449372360f-goog Message-ID: <20250808152850.2580887-3-surenb@google.com> Subject: [PATCH v4 2/3] fs/proc/task_mmu: factor out proc_maps_private fields used by PROCMAP_QUERY From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, david@redhat.com, vbabka@suse.cz, peterx@redhat.com, jannh@google.com, hannes@cmpxchg.org, mhocko@kernel.org, paulmck@kernel.org, shuah@kernel.org, adobriyan@gmail.com, brauner@kernel.org, josef@toxicpanda.com, yebin10@huawei.com, linux@weissschuh.net, willy@infradead.org, osalvador@suse.de, andrii@kernel.org, ryan.roberts@arm.com, christophe.leroy@csgroup.eu, tjmercier@google.com, kaleshsingh@google.com, aha310510@gmail.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, surenb@google.com, SeongJae Park Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Refactor struct proc_maps_private so that the fields used by PROCMAP_QUERY ioctl are moved into a separate structure. In the next patch this allows ioctl to reuse some of the functions used for reading /proc/pid/maps without using file->private_data. This prevents concurrent modification of file->private_data members by ioctl and /proc/pid/maps readers. The change is pure code refactoring and has no functional changes. Signed-off-by: Suren Baghdasaryan Reviewed-by: Vlastimil Babka Acked-by: SeongJae Park Reviewed-by: Lorenzo Stoakes --- fs/proc/internal.h | 15 +++++--- fs/proc/task_mmu.c | 87 +++++++++++++++++++++++--------------------- fs/proc/task_nommu.c | 14 +++---- 3 files changed, 63 insertions(+), 53 deletions(-) diff --git a/fs/proc/internal.h b/fs/proc/internal.h index e737401d7383..d1598576506c 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -378,16 +378,21 @@ extern void proc_self_init(void); * task_[no]mmu.c */ struct mem_size_stats; -struct proc_maps_private { - struct inode *inode; - struct task_struct *task; + +struct proc_maps_locking_ctx { struct mm_struct *mm; - struct vma_iterator iter; - loff_t last_pos; #ifdef CONFIG_PER_VMA_LOCK bool mmap_locked; struct vm_area_struct *locked_vma; #endif +}; + +struct proc_maps_private { + struct inode *inode; + struct task_struct *task; + struct vma_iterator iter; + loff_t last_pos; + struct proc_maps_locking_ctx lock_ctx; #ifdef CONFIG_NUMA struct mempolicy *task_mempolicy; #endif diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 29cca0e6d0ff..c0968d293b61 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -132,18 +132,18 @@ static void release_task_mempolicy(struct proc_maps_p= rivate *priv) =20 #ifdef CONFIG_PER_VMA_LOCK =20 -static void unlock_vma(struct proc_maps_private *priv) +static void unlock_ctx_vma(struct proc_maps_locking_ctx *lock_ctx) { - if (priv->locked_vma) { - vma_end_read(priv->locked_vma); - priv->locked_vma =3D NULL; + if (lock_ctx->locked_vma) { + vma_end_read(lock_ctx->locked_vma); + lock_ctx->locked_vma =3D NULL; } } =20 static const struct seq_operations proc_pid_maps_op; =20 static inline bool lock_vma_range(struct seq_file *m, - struct proc_maps_private *priv) + struct proc_maps_locking_ctx *lock_ctx) { /* * smaps and numa_maps perform page table walk, therefore require @@ -151,25 +151,25 @@ static inline bool lock_vma_range(struct seq_file *m, * walking the vma tree under rcu read protection. */ if (m->op !=3D &proc_pid_maps_op) { - if (mmap_read_lock_killable(priv->mm)) + if (mmap_read_lock_killable(lock_ctx->mm)) return false; =20 - priv->mmap_locked =3D true; + lock_ctx->mmap_locked =3D true; } else { rcu_read_lock(); - priv->locked_vma =3D NULL; - priv->mmap_locked =3D false; + lock_ctx->locked_vma =3D NULL; + lock_ctx->mmap_locked =3D false; } =20 return true; } =20 -static inline void unlock_vma_range(struct proc_maps_private *priv) +static inline void unlock_vma_range(struct proc_maps_locking_ctx *lock_ctx) { - if (priv->mmap_locked) { - mmap_read_unlock(priv->mm); + if (lock_ctx->mmap_locked) { + mmap_read_unlock(lock_ctx->mm); } else { - unlock_vma(priv); + unlock_ctx_vma(lock_ctx); rcu_read_unlock(); } } @@ -177,15 +177,16 @@ static inline void unlock_vma_range(struct proc_maps_= private *priv) static struct vm_area_struct *get_next_vma(struct proc_maps_private *priv, loff_t last_pos) { + struct proc_maps_locking_ctx *lock_ctx =3D &priv->lock_ctx; struct vm_area_struct *vma; =20 - if (priv->mmap_locked) + if (lock_ctx->mmap_locked) return vma_next(&priv->iter); =20 - unlock_vma(priv); - vma =3D lock_next_vma(priv->mm, &priv->iter, last_pos); + unlock_ctx_vma(lock_ctx); + vma =3D lock_next_vma(lock_ctx->mm, &priv->iter, last_pos); if (!IS_ERR_OR_NULL(vma)) - priv->locked_vma =3D vma; + lock_ctx->locked_vma =3D vma; =20 return vma; } @@ -193,14 +194,16 @@ static struct vm_area_struct *get_next_vma(struct pro= c_maps_private *priv, static inline bool fallback_to_mmap_lock(struct proc_maps_private *priv, loff_t pos) { - if (priv->mmap_locked) + struct proc_maps_locking_ctx *lock_ctx =3D &priv->lock_ctx; + + if (lock_ctx->mmap_locked) return false; =20 rcu_read_unlock(); - mmap_read_lock(priv->mm); + mmap_read_lock(lock_ctx->mm); /* Reinitialize the iterator after taking mmap_lock */ vma_iter_set(&priv->iter, pos); - priv->mmap_locked =3D true; + lock_ctx->mmap_locked =3D true; =20 return true; } @@ -208,14 +211,14 @@ static inline bool fallback_to_mmap_lock(struct proc_= maps_private *priv, #else /* CONFIG_PER_VMA_LOCK */ =20 static inline bool lock_vma_range(struct seq_file *m, - struct proc_maps_private *priv) + struct proc_maps_locking_ctx *lock_ctx) { - return mmap_read_lock_killable(priv->mm) =3D=3D 0; + return mmap_read_lock_killable(lock_ctx->mm) =3D=3D 0; } =20 -static inline void unlock_vma_range(struct proc_maps_private *priv) +static inline void unlock_vma_range(struct proc_maps_locking_ctx *lock_ctx) { - mmap_read_unlock(priv->mm); + mmap_read_unlock(lock_ctx->mm); } =20 static struct vm_area_struct *get_next_vma(struct proc_maps_private *priv, @@ -258,7 +261,7 @@ static struct vm_area_struct *proc_get_vma(struct seq_f= ile *m, loff_t *ppos) *ppos =3D vma->vm_end; } else { *ppos =3D SENTINEL_VMA_GATE; - vma =3D get_gate_vma(priv->mm); + vma =3D get_gate_vma(priv->lock_ctx.mm); } =20 return vma; @@ -267,6 +270,7 @@ static struct vm_area_struct *proc_get_vma(struct seq_f= ile *m, loff_t *ppos) static void *m_start(struct seq_file *m, loff_t *ppos) { struct proc_maps_private *priv =3D m->private; + struct proc_maps_locking_ctx *lock_ctx; loff_t last_addr =3D *ppos; struct mm_struct *mm; =20 @@ -278,14 +282,15 @@ static void *m_start(struct seq_file *m, loff_t *ppos) if (!priv->task) return ERR_PTR(-ESRCH); =20 - mm =3D priv->mm; + lock_ctx =3D &priv->lock_ctx; + mm =3D lock_ctx->mm; if (!mm || !mmget_not_zero(mm)) { put_task_struct(priv->task); priv->task =3D NULL; return NULL; } =20 - if (!lock_vma_range(m, priv)) { + if (!lock_vma_range(m, lock_ctx)) { mmput(mm); put_task_struct(priv->task); priv->task =3D NULL; @@ -318,13 +323,13 @@ static void *m_next(struct seq_file *m, void *v, loff= _t *ppos) static void m_stop(struct seq_file *m, void *v) { struct proc_maps_private *priv =3D m->private; - struct mm_struct *mm =3D priv->mm; + struct mm_struct *mm =3D priv->lock_ctx.mm; =20 if (!priv->task) return; =20 release_task_mempolicy(priv); - unlock_vma_range(priv); + unlock_vma_range(&priv->lock_ctx); mmput(mm); put_task_struct(priv->task); priv->task =3D NULL; @@ -339,9 +344,9 @@ static int proc_maps_open(struct inode *inode, struct f= ile *file, return -ENOMEM; =20 priv->inode =3D inode; - priv->mm =3D proc_mem_open(inode, PTRACE_MODE_READ); - if (IS_ERR(priv->mm)) { - int err =3D PTR_ERR(priv->mm); + priv->lock_ctx.mm =3D proc_mem_open(inode, PTRACE_MODE_READ); + if (IS_ERR(priv->lock_ctx.mm)) { + int err =3D PTR_ERR(priv->lock_ctx.mm); =20 seq_release_private(inode, file); return err; @@ -355,8 +360,8 @@ static int proc_map_release(struct inode *inode, struct= file *file) struct seq_file *seq =3D file->private_data; struct proc_maps_private *priv =3D seq->private; =20 - if (priv->mm) - mmdrop(priv->mm); + if (priv->lock_ctx.mm) + mmdrop(priv->lock_ctx.mm); =20 return seq_release_private(inode, file); } @@ -610,7 +615,7 @@ static int do_procmap_query(struct proc_maps_private *p= riv, void __user *uarg) if (!!karg.build_id_size !=3D !!karg.build_id_addr) return -EINVAL; =20 - mm =3D priv->mm; + mm =3D priv->lock_ctx.mm; if (!mm || !mmget_not_zero(mm)) return -ESRCH; =20 @@ -1311,7 +1316,7 @@ static int show_smaps_rollup(struct seq_file *m, void= *v) { struct proc_maps_private *priv =3D m->private; struct mem_size_stats mss =3D {}; - struct mm_struct *mm =3D priv->mm; + struct mm_struct *mm =3D priv->lock_ctx.mm; struct vm_area_struct *vma; unsigned long vma_start =3D 0, last_vma_end =3D 0; int ret =3D 0; @@ -1456,9 +1461,9 @@ static int smaps_rollup_open(struct inode *inode, str= uct file *file) goto out_free; =20 priv->inode =3D inode; - priv->mm =3D proc_mem_open(inode, PTRACE_MODE_READ); - if (IS_ERR_OR_NULL(priv->mm)) { - ret =3D priv->mm ? PTR_ERR(priv->mm) : -ESRCH; + priv->lock_ctx.mm =3D proc_mem_open(inode, PTRACE_MODE_READ); + if (IS_ERR_OR_NULL(priv->lock_ctx.mm)) { + ret =3D priv->lock_ctx.mm ? PTR_ERR(priv->lock_ctx.mm) : -ESRCH; =20 single_release(inode, file); goto out_free; @@ -1476,8 +1481,8 @@ static int smaps_rollup_release(struct inode *inode, = struct file *file) struct seq_file *seq =3D file->private_data; struct proc_maps_private *priv =3D seq->private; =20 - if (priv->mm) - mmdrop(priv->mm); + if (priv->lock_ctx.mm) + mmdrop(priv->lock_ctx.mm); =20 kfree(priv); return single_release(inode, file); diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c index 59bfd61d653a..d362919f4f68 100644 --- a/fs/proc/task_nommu.c +++ b/fs/proc/task_nommu.c @@ -204,7 +204,7 @@ static void *m_start(struct seq_file *m, loff_t *ppos) if (!priv->task) return ERR_PTR(-ESRCH); =20 - mm =3D priv->mm; + mm =3D priv->lock_ctx.mm; if (!mm || !mmget_not_zero(mm)) { put_task_struct(priv->task); priv->task =3D NULL; @@ -226,7 +226,7 @@ static void *m_start(struct seq_file *m, loff_t *ppos) static void m_stop(struct seq_file *m, void *v) { struct proc_maps_private *priv =3D m->private; - struct mm_struct *mm =3D priv->mm; + struct mm_struct *mm =3D priv->lock_ctx.mm; =20 if (!priv->task) return; @@ -259,9 +259,9 @@ static int maps_open(struct inode *inode, struct file *= file, return -ENOMEM; =20 priv->inode =3D inode; - priv->mm =3D proc_mem_open(inode, PTRACE_MODE_READ); - if (IS_ERR_OR_NULL(priv->mm)) { - int err =3D priv->mm ? PTR_ERR(priv->mm) : -ESRCH; + priv->lock_ctx.mm =3D proc_mem_open(inode, PTRACE_MODE_READ); + if (IS_ERR_OR_NULL(priv->lock_ctx.mm)) { + int err =3D priv->lock_ctx.mm ? PTR_ERR(priv->lock_ctx.mm) : -ESRCH; =20 seq_release_private(inode, file); return err; @@ -276,8 +276,8 @@ static int map_release(struct inode *inode, struct file= *file) struct seq_file *seq =3D file->private_data; struct proc_maps_private *priv =3D seq->private; =20 - if (priv->mm) - mmdrop(priv->mm); + if (priv->lock_ctx.mm) + mmdrop(priv->lock_ctx.mm); =20 return seq_release_private(inode, file); } --=20 2.50.1.703.g449372360f-goog