From nobody Sat Jul 25 05:28:14 2026 Received: from fanzine2.igalia.com (fanzine2.igalia.com [213.97.179.56]) (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 776C2417BFF; Fri, 17 Jul 2026 13:55:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.97.179.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784296520; cv=none; b=TiWa2duC/ImOCaI3sABRL6XtlgPDnRPbvdPDCSGvTtEotjuqWJz34YhMTGsdbu9H3okmpQGeEH3WxNR9Tlyu6vhdOsOfzFjoIviyIOGiJd7pUvQnY2UC/LmwgTKMVBiFANUhwWfJzQm4d9Dv4sEa+qAJUj8kO7Vm0m4Y692gHCc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784296520; c=relaxed/simple; bh=xHcu9LeQao5cCzS2t1hd8WM6BB/2QX/SD8WWVcqH1dg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=SEP0/vXpK2iJ79vdw+kregHumtyc2ZvM6PlHlTl4M6TObDsiPY4Dz2DCfau29x+i9qxHUucR69Upuk6C0Fry/uNINpto2cbgEYoLjFr5z5M4l6FP3V/7gQ0tdAtQWpFrJHFo8MmVM1h9y+v4eVrTLBMGGv6TIYzAy2v19FTlovE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=igalia.com; spf=pass smtp.mailfrom=igalia.com; dkim=pass (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b=crNEzaop; arc=none smtp.client-ip=213.97.179.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=igalia.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=igalia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b="crNEzaop" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Cc:To:Message-Id:Content-Transfer-Encoding:Content-Type: MIME-Version:Subject:Date:From:From:Reply-To; bh=TXBBgafLlIitdIEusehCJN5MB+jax7+RPOwi0bDdWNk=; b=crNEzaopE/vY/f0zlVtxtjorsf AAurL7zs+keZoRv5ny6rnajG1LQki2zFIsQdyDoLsuU8R9f84baoYCYkExhY4x5YqEg0NwPFrUkqI 2U8eN107afO7cISvzRcLEFllrxnhiXmWa03eVNTpQ1KUvNcmS/SGFPNeRRaWt6L93ehjCSCl7yByv SBKJpvQFmDPAm1kzgrtbXpDLNKDQJJ5UmMUWva3KxwSrdgYt1jBu4tAmRIC4FPM8QBHn8a7E9LqI5 V2tShzJ7BT+c3kbLjyNSrguy51eOeeJZtLz58s19xsAHzD+Sp3q1YZNsVX+/F7OGYU2FmmsLW0f4L vmsoAGaw==; Received: from [179.118.191.219] (helo=[192.168.15.100]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1wkj1q-00GXeM-2N; Fri, 17 Jul 2026 15:55:02 +0200 From: =?utf-8?q?Andr=C3=A9_Almeida?= Date: Fri, 17 Jul 2026 10:54:34 -0300 Subject: [PATCH v4 1/6] treewide: Get rid of get_task_comm() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260717-tonyk-long_name-v4-1-1fedfc870d21@igalia.com> References: <20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com> In-Reply-To: <20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com> To: Peter Zijlstra , Juri Lelli , Vincent Guittot , Steven Rostedt , Christian Brauner , Kees Cook , Shuah Khan , willy@infradead.org, mathieu.desnoyers@efficios.com, David Laight , Linus Torvalds , akpm@linux-foundation.org, Yafang Shao , andrii.nakryiko@gmail.com, arnaldo.melo@gmail.com, Petr Mladek Cc: linux-kernel@vger.kernel.org, kernel-dev@igalia.com, linux-mm@kvack.org, linux-api@vger.kernel.org, =?utf-8?q?Andr=C3=A9_Almeida?= X-Mailer: b4 0.15.2 Since commit 4cc0473d7754 ("get rid of __get_task_comm()"), get_task_comm() does just a redundant check for the buffer size and call strscpy_pad(). Replace get_task_comm() calls with strscpy_pad(), that will do the right thing if the buffers sizes doesn't match: zero-pad if it's bigger, and truncate if it's smaller. Link: https://lore.kernel.org/lkml/CAHk-=3Dwi5c=3D_-FBGo_88CowJd_F-Gi6Ud9d= =3DTALm65ReN7YjrMw@mail.gmail.com/ Signed-off-by: Andr=C3=A9 Almeida --- Changes from v1: - Fix for security/ipe/audit.c and net/netfilter/nf_tables_api.c --- drivers/connector/cn_proc.c | 2 +- drivers/dma-buf/sw_sync.c | 2 +- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c | 2 +- drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c | 2 +- drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 2 +- drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c | 2 +- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 4 ++-- drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 2 +- drivers/gpu/drm/lima/lima_ctx.c | 2 +- drivers/gpu/drm/panfrost/panfrost_gem.c | 2 +- drivers/gpu/drm/panthor/panthor_gem.c | 2 +- drivers/gpu/drm/panthor/panthor_sched.c | 2 +- drivers/gpu/drm/virtio/virtgpu_ioctl.c | 2 +- drivers/hwtracing/stm/core.c | 2 +- drivers/tty/tty_audit.c | 2 +- fs/binfmt_elf.c | 2 +- fs/binfmt_elf_fdpic.c | 2 +- fs/proc/array.c | 2 +- include/linux/sched.h | 19 ------------------- kernel/audit.c | 6 ++++-- kernel/auditsc.c | 6 ++++-- kernel/printk/printk.c | 2 +- kernel/sys.c | 2 +- net/bluetooth/hci_sock.c | 2 +- net/netfilter/nf_tables_api.c | 4 +++- security/integrity/integrity_audit.c | 3 ++- security/ipe/audit.c | 3 ++- security/landlock/domain.c | 2 +- security/lsm_audit.c | 7 ++++--- 29 files changed, 42 insertions(+), 52 deletions(-) diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c index 0056ab81fbc3..c78243ed3c2a 100644 --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -278,7 +278,7 @@ void proc_comm_connector(struct task_struct *task) ev->what =3D PROC_EVENT_COMM; ev->event_data.comm.process_pid =3D task->pid; ev->event_data.comm.process_tgid =3D task->tgid; - get_task_comm(ev->event_data.comm.comm, task); + strscpy_pad(ev->event_data.comm.comm, task->comm); =20 memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); msg->ack =3D 0; /* not used */ diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c index 8df20b0218a9..d501657ad801 100644 --- a/drivers/dma-buf/sw_sync.c +++ b/drivers/dma-buf/sw_sync.c @@ -312,7 +312,7 @@ static int sw_sync_debugfs_open(struct inode *inode, st= ruct file *file) struct sync_timeline *obj; char task_comm[TASK_COMM_LEN]; =20 - get_task_comm(task_comm, current); + strscpy_pad(task_comm, current->comm); =20 obj =3D sync_timeline_create(task_comm); if (!obj) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c b/drivers/gpu= /drm/amd/amdgpu/amdgpu_amdkfd_fence.c index 6a364357522b..13c8857e4ffb 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c @@ -74,7 +74,7 @@ struct amdgpu_amdkfd_fence *amdgpu_amdkfd_fence_create(u6= 4 context, /* This reference gets released in amdkfd_fence_release */ mmgrab(mm); fence->mm =3D mm; - get_task_comm(fence->timeline_name, current); + strscpy_pad(fence->timeline_name, current->comm); spin_lock_init(&fence->lock); fence->svm_bo =3D svm_bo; fence->context_id =3D context_id; diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c b/drivers/g= pu/drm/amd/amdgpu/amdgpu_eviction_fence.c index f6b7522c3c82..046243e3a3cd 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c @@ -128,7 +128,7 @@ int amdgpu_evf_mgr_rearm(struct amdgpu_eviction_fence_m= gr *evf_mgr, return -ENOMEM; =20 ev_fence->evf_mgr =3D evf_mgr; - get_task_comm(ev_fence->timeline_name, current); + strscpy_pad(ev_fence->timeline_name, current->comm); spin_lock_init(&ev_fence->lock); dma_fence_init64(&ev_fence->base, &amdgpu_eviction_fence_ops, &ev_fence->lock, evf_mgr->ev_fence_ctx, diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c b/drivers/gpu/drm/amd/= amdgpu/amdgpu_ras.c index 764cd4950408..e60a470b57ec 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c @@ -4445,7 +4445,7 @@ int amdgpu_ras_init(struct amdgpu_device *adev) } =20 con->init_task_pid =3D task_pid_nr(current); - get_task_comm(con->init_task_comm, current); + strscpy_pad(con->init_task_comm, current->comm); =20 mutex_init(&con->critical_region_lock); INIT_LIST_HEAD(&con->critical_region_head); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/= drm/amd/amdgpu/amdgpu_userq_fence.c index f74ad378e407..f41857473641 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c @@ -85,7 +85,7 @@ int amdgpu_userq_fence_driver_alloc(struct amdgpu_device = *adev, =20 fence_drv->adev =3D adev; fence_drv->context =3D dma_fence_context_alloc(1); - get_task_comm(fence_drv->timeline_name, current); + strscpy_pad(fence_drv->timeline_name, current->comm); =20 *fence_drv_req =3D fence_drv; =20 diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/a= mdgpu/amdgpu_vm.c index bb99b7c3a010..84c0b310e9c1 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -2542,10 +2542,10 @@ void amdgpu_vm_set_task_info(struct amdgpu_vm *vm) return; =20 vm->task_info->task.pid =3D current->pid; - get_task_comm(vm->task_info->task.comm, current); + strscpy_pad(vm->task_info->task.comm, current->comm); =20 vm->task_info->tgid =3D current->tgid; - get_task_comm(vm->task_info->process_name, current->group_leader); + strscpy_pad(vm->task_info->process_name, current->group_leader->comm); } =20 /** diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm= /amd/amdgpu/amdgpu_vram_mgr.c index 2a241a5b12c4..f8ce59d8587a 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c @@ -563,7 +563,7 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_mana= ger *man, } =20 vres->task.pid =3D task_pid_nr(current); - get_task_comm(vres->task.comm, current); + strscpy_pad(vres->task.comm, current->comm); list_add_tail(&vres->vres_node, &mgr->allocated_vres_list); =20 if (bo->flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS && adjust_dcc_size) { diff --git a/drivers/gpu/drm/lima/lima_ctx.c b/drivers/gpu/drm/lima/lima_ct= x.c index 68ede7a725e2..e8c5c3601bf1 100644 --- a/drivers/gpu/drm/lima/lima_ctx.c +++ b/drivers/gpu/drm/lima/lima_ctx.c @@ -29,7 +29,7 @@ int lima_ctx_create(struct lima_device *dev, struct lima_= ctx_mgr *mgr, u32 *id) goto err_out0; =20 ctx->pid =3D task_pid_nr(current); - get_task_comm(ctx->pname, current); + strscpy_pad(ctx->pname, current->comm); =20 return 0; =20 diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panf= rost/panfrost_gem.c index 3a7fce428898..11936c4d3573 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c @@ -36,7 +36,7 @@ static void panfrost_gem_debugfs_bo_add(struct panfrost_d= evice *pfdev, struct panfrost_gem_object *bo) { bo->debugfs.creator.tgid =3D current->tgid; - get_task_comm(bo->debugfs.creator.process_name, current->group_leader); + strscpy_pad(bo->debugfs.creator.process_name, current->group_leader->comm= ); =20 mutex_lock(&pfdev->debugfs.gems_lock); list_add_tail(&bo->debugfs.node, &pfdev->debugfs.gems_list); diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/pantho= r/panthor_gem.c index a1e2eb1ca7bb..ebb3664e4303 100644 --- a/drivers/gpu/drm/panthor/panthor_gem.c +++ b/drivers/gpu/drm/panthor/panthor_gem.c @@ -54,7 +54,7 @@ static void panthor_gem_debugfs_bo_add(struct panthor_gem= _object *bo) struct panthor_device, base); =20 bo->debugfs.creator.tgid =3D current->tgid; - get_task_comm(bo->debugfs.creator.process_name, current->group_leader); + strscpy_pad(bo->debugfs.creator.process_name, current->group_leader->comm= ); =20 mutex_lock(&ptdev->gems.lock); list_add_tail(&bo->debugfs.node, &ptdev->gems.node); diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/pant= hor/panthor_sched.c index 298b046c95ed..81c4659c0d7b 100644 --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -3617,7 +3617,7 @@ static void group_init_task_info(struct panthor_group= *group) struct task_struct *task =3D current->group_leader; =20 group->task_info.pid =3D task->pid; - get_task_comm(group->task_info.comm, task); + strscpy_pad(group->task_info.comm, task->comm); } =20 static void add_group_kbo_sizes(struct panthor_device *ptdev, diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virti= o/virtgpu_ioctl.c index 3d8e4ccdb7c1..b10a0e1cb1ed 100644 --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c @@ -50,7 +50,7 @@ static void virtio_gpu_create_context_locked(struct virti= o_gpu_device *vgdev, } else { char dbgname[TASK_COMM_LEN]; =20 - get_task_comm(dbgname, current); + strscpy_pad(dbgname, current->comm); virtio_gpu_cmd_context_create(vgdev, vfpriv->ctx_id, vfpriv->context_init, strlen(dbgname), dbgname); diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c index f48c6a8a0654..c7715439964e 100644 --- a/drivers/hwtracing/stm/core.c +++ b/drivers/hwtracing/stm/core.c @@ -634,7 +634,7 @@ static ssize_t stm_char_write(struct file *file, const = char __user *buf, char comm[sizeof(current->comm)]; char *ids[] =3D { comm, "default", NULL }; =20 - get_task_comm(comm, current); + strscpy_pad(comm, current->comm); =20 err =3D stm_assign_first_policy(stmf->stm, &stmf->output, ids, 1); /* diff --git a/drivers/tty/tty_audit.c b/drivers/tty/tty_audit.c index d014af6ab060..d514a81d0a5c 100644 --- a/drivers/tty/tty_audit.c +++ b/drivers/tty/tty_audit.c @@ -77,7 +77,7 @@ static void tty_audit_log(const char *description, dev_t = dev, audit_log_format(ab, "%s pid=3D%u uid=3D%u auid=3D%u ses=3D%u major=3D%d = minor=3D%d comm=3D", description, pid, uid, loginuid, sessionid, MAJOR(dev), MINOR(dev)); - get_task_comm(name, current); + strscpy_pad(name, current->comm); audit_log_untrustedstring(ab, name); audit_log_format(ab, " data=3D"); audit_log_n_hex(ab, data, size); diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 16a56b6b3f6c..d25922460b63 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1557,7 +1557,7 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, s= truct task_struct *p, SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid)); SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid)); rcu_read_unlock(); - get_task_comm(psinfo->pr_fname, p); + strscpy_pad(psinfo->pr_fname, p->comm); =20 return 0; } diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index 7e3108489c83..c4d4e59ff34d 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1371,7 +1371,7 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, s= truct task_struct *p, SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid)); SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid)); rcu_read_unlock(); - get_task_comm(psinfo->pr_fname, p); + strscpy_pad(psinfo->pr_fname, p->comm); =20 return 0; } diff --git a/fs/proc/array.c b/fs/proc/array.c index 479ea8cb4ef4..905d910b598f 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -110,7 +110,7 @@ void proc_task_name(struct seq_file *m, struct task_str= uct *p, bool escape) else if (p->flags & PF_KTHREAD) get_kthread_comm(tcomm, sizeof(tcomm), p); else - get_task_comm(tcomm, p); + strscpy_pad(tcomm, p->comm); =20 if (escape) seq_escape_str(m, tcomm, ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\"); diff --git a/include/linux/sched.h b/include/linux/sched.h index 373bcc0598d1..2714c81bc708 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2021,25 +2021,6 @@ extern void __set_task_comm(struct task_struct *tsk,= const char *from, bool exec __set_task_comm(tsk, from, false); \ }) =20 -/* - * - Why not use task_lock()? - * User space can randomly change their names anyway, so locking for rea= ders - * doesn't make sense. For writers, locking is probably necessary, as a = race - * condition could lead to long-term mixed results. - * The strscpy_pad() in __set_task_comm() can ensure that the task comm = is - * always NUL-terminated and zero-padded. Therefore the race condition b= etween - * reader and writer is not an issue. - * - * - BUILD_BUG_ON() can help prevent the buf from being truncated. - * Since the callers don't perform any return value checks, this safegua= rd is - * necessary. - */ -#define get_task_comm(buf, tsk) ({ \ - BUILD_BUG_ON(sizeof(buf) < TASK_COMM_LEN); \ - strscpy_pad(buf, (tsk)->comm); \ - buf; \ -}) - static __always_inline void scheduler_ipi(void) { /* diff --git a/kernel/audit.c b/kernel/audit.c index 562476937fa7..1f0b44d4e5c7 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1667,7 +1667,8 @@ static void audit_log_multicast(int group, const char= *op, int err) audit_put_tty(tty); audit_log_task_context(ab); /* subj=3D */ audit_log_format(ab, " comm=3D"); - audit_log_untrustedstring(ab, get_task_comm(comm, current)); + strscpy_pad(comm, current->comm); + audit_log_untrustedstring(ab, comm); audit_log_d_path_exe(ab, current->mm); /* exe=3D */ audit_log_format(ab, " nl-mcgrp=3D%d op=3D%s res=3D%d", group, op, !err); audit_log_end(ab); @@ -2476,7 +2477,8 @@ void audit_log_task_info(struct audit_buffer *ab) audit_get_sessionid(current)); audit_put_tty(tty); audit_log_format(ab, " comm=3D"); - audit_log_untrustedstring(ab, get_task_comm(comm, current)); + strscpy_pad(comm, current->comm); + audit_log_untrustedstring(ab, comm); audit_log_d_path_exe(ab, current->mm); audit_log_task_context(ab); } diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 6610e667c728..1d930f169856 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -2877,7 +2877,8 @@ void __audit_log_nfcfg(const char *name, u8 af, unsig= ned int nentries, audit_log_format(ab, " pid=3D%u", task_tgid_nr(current)); audit_log_task_context(ab); /* subj=3D */ audit_log_format(ab, " comm=3D"); - audit_log_untrustedstring(ab, get_task_comm(comm, current)); + strscpy_pad(comm, current->comm); + audit_log_untrustedstring(ab, comm); audit_log_end(ab); } EXPORT_SYMBOL_GPL(__audit_log_nfcfg); @@ -2900,7 +2901,8 @@ static void audit_log_task(struct audit_buffer *ab) sessionid); audit_log_task_context(ab); audit_log_format(ab, " pid=3D%d comm=3D", task_tgid_nr(current)); - audit_log_untrustedstring(ab, get_task_comm(comm, current)); + strscpy_pad(comm, current->comm); + audit_log_untrustedstring(ab, comm); audit_log_d_path_exe(ab, current->mm); } =20 diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 2fe9a963c823..019b11de262c 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2247,7 +2247,7 @@ static u16 printk_sprint(char *text, u16 size, int fa= cility, static void printk_store_execution_ctx(struct printk_info *info) { info->caller_id2 =3D printk_caller_id2(); - get_task_comm(info->comm, current); + strscpy_pad(info->comm, current->comm); } =20 static void pmsg_load_execution_ctx(struct printk_message *pmsg, diff --git a/kernel/sys.c b/kernel/sys.c index df69bd71de03..74c22d6dded0 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2609,7 +2609,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, ar= g2, unsigned long, arg3, proc_comm_connector(me); break; case PR_GET_NAME: - get_task_comm(comm, me); + strscpy_pad(comm, me->comm); if (copy_to_user((char __user *)arg2, comm, sizeof(comm))) return -EFAULT; break; diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c index 070ca388f9ac..4e66cb2d9549 100644 --- a/net/bluetooth/hci_sock.c +++ b/net/bluetooth/hci_sock.c @@ -104,7 +104,7 @@ static bool hci_sock_gen_cookie(struct sock *sk) id =3D 0xffffffff; =20 hci_pi(sk)->cookie =3D id; - get_task_comm(hci_pi(sk)->comm, current); + strscpy_pad(hci_pi(sk)->comm, current->comm); return true; } =20 diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index a9eaf9455c77..c5555eed1b62 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -9718,9 +9718,11 @@ static int nf_tables_fill_gen_info(struct sk_buff *s= kb, struct net *net, if (!nlh) goto nla_put_failure; =20 + strscpy_pad(buf, current->comm); + if (nla_put_be32(skb, NFTA_GEN_ID, htonl(nft_base_seq(net))) || nla_put_be32(skb, NFTA_GEN_PROC_PID, htonl(task_pid_nr(current))) || - nla_put_string(skb, NFTA_GEN_PROC_NAME, get_task_comm(buf, current))) + nla_put_string(skb, NFTA_GEN_PROC_NAME, buf)) goto nla_put_failure; =20 nlmsg_end(skb, nlh); diff --git a/security/integrity/integrity_audit.c b/security/integrity/inte= grity_audit.c index d8d9e5ff1cd2..98060060929d 100644 --- a/security/integrity/integrity_audit.c +++ b/security/integrity/integrity_audit.c @@ -54,7 +54,8 @@ void integrity_audit_message(int audit_msgno, struct inod= e *inode, audit_get_sessionid(current)); audit_log_task_context(ab); audit_log_format(ab, " op=3D%s cause=3D%s comm=3D", op, cause); - audit_log_untrustedstring(ab, get_task_comm(name, current)); + strscpy_pad(name, current->comm); + audit_log_untrustedstring(ab, name); if (fname) { audit_log_format(ab, " name=3D"); audit_log_untrustedstring(ab, fname); diff --git a/security/ipe/audit.c b/security/ipe/audit.c index 93fb59fbddd6..90a6acfb7cdf 100644 --- a/security/ipe/audit.c +++ b/security/ipe/audit.c @@ -145,7 +145,8 @@ void ipe_audit_match(const struct ipe_eval_ctx *const c= tx, audit_log_format(ab, "ipe_op=3D%s ipe_hook=3D%s enforcing=3D%d pid=3D%d c= omm=3D", op, audit_hook_names[ctx->hook], READ_ONCE(enforce), task_tgid_nr(current)); - audit_log_untrustedstring(ab, get_task_comm(comm, current)); + strscpy_pad(comm, current->comm); + audit_log_untrustedstring(ab, comm); =20 if (ctx->file) { audit_log_d_path(ab, " path=3D", &ctx->file->f_path); diff --git a/security/landlock/domain.c b/security/landlock/domain.c index 9a8355fccd26..b2fc7f722d69 100644 --- a/security/landlock/domain.c +++ b/security/landlock/domain.c @@ -102,7 +102,7 @@ static struct landlock_details *get_current_details(voi= d) memcpy(details->exe_path, path_str, path_size); details->pid =3D get_pid(task_tgid(current)); details->uid =3D from_kuid(&init_user_ns, current_uid()); - get_task_comm(details->comm, current); + strscpy_pad(details->comm, current->comm); return details; } =20 diff --git a/security/lsm_audit.c b/security/lsm_audit.c index 737f5a263a8f..a587ffecd985 100644 --- a/security/lsm_audit.c +++ b/security/lsm_audit.c @@ -276,8 +276,8 @@ void audit_log_lsm_data(struct audit_buffer *ab, if (pid) { char tskcomm[sizeof(tsk->comm)]; audit_log_format(ab, " opid=3D%d ocomm=3D", pid); 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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260717-tonyk-long_name-v4-2-1fedfc870d21@igalia.com> References: <20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com> In-Reply-To: <20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com> To: Peter Zijlstra , Juri Lelli , Vincent Guittot , Steven Rostedt , Christian Brauner , Kees Cook , Shuah Khan , willy@infradead.org, mathieu.desnoyers@efficios.com, David Laight , Linus Torvalds , akpm@linux-foundation.org, Yafang Shao , andrii.nakryiko@gmail.com, arnaldo.melo@gmail.com, Petr Mladek Cc: linux-kernel@vger.kernel.org, kernel-dev@igalia.com, linux-mm@kvack.org, linux-api@vger.kernel.org, =?utf-8?q?Andr=C3=A9_Almeida?= X-Mailer: b4 0.15.2 In order to increase the size of current->comm[] and to avoid breaking any existing code, replace memcpy() with copy_task_comm(). This new function makes sure that the copy is NUL terminated. This is crucial given that the source buffer might be larger than the destination buffer and could truncate the NUL character out of it. Signed-off-by: Andr=C3=A9 Almeida --- Changes from v3: - Simplify copy_task_comm() to a memcpy + NUL char at the end of buffer Changes from v2: - Bring back custom function. Changes from v1: - New patch, dropped strtostr() from last version --- include/linux/coredump.h | 2 +- include/linux/sched.h | 11 +++++++++++ include/linux/tracepoint.h | 4 ++-- include/trace/events/block.h | 10 +++++----- include/trace/events/coredump.h | 2 +- include/trace/events/f2fs.h | 4 ++-- include/trace/events/oom.h | 2 +- include/trace/events/osnoise.h | 2 +- include/trace/events/sched.h | 10 +++++----- include/trace/events/signal.h | 2 +- include/trace/events/task.h | 7 ++++--- kernel/printk/nbcon.c | 2 +- kernel/printk/printk.c | 2 +- 13 files changed, 36 insertions(+), 24 deletions(-) diff --git a/include/linux/coredump.h b/include/linux/coredump.h index 7b38ee2e7913..dee82e3c350a 100644 --- a/include/linux/coredump.h +++ b/include/linux/coredump.h @@ -58,7 +58,7 @@ extern void vfs_coredump(const kernel_siginfo_t *siginfo); do { \ char comm[TASK_COMM_LEN]; \ /* This will always be NUL terminated. */ \ - memcpy(comm, current->comm, sizeof(comm)); \ + copy_task_comm(comm, current, sizeof(comm)); \ printk_ratelimited(Level "coredump: %d(%*pE): " Format "\n", \ task_tgid_vnr(current), (int)strlen(comm), comm, ##__VA_ARGS__); \ } while (0) \ diff --git a/include/linux/sched.h b/include/linux/sched.h index 2714c81bc708..9b6a413f6618 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2021,6 +2021,17 @@ extern void __set_task_comm(struct task_struct *tsk,= const char *from, bool exec __set_task_comm(tsk, from, false); \ }) =20 +/* + * Copy task name to a buffer. Final result is always a NUL-terminated str= ing. + */ +static __always_inline void copy_task_comm(char *dst, struct task_struct *= tsk, size_t len) +{ + const char *_src =3D tsk->comm; + + memcpy(dst, _src, len); + dst[len - 1] =3D '\0'; +} + static __always_inline void scheduler_ipi(void) { /* diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index e0d838c9ce93..9b0094fa44c6 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -637,10 +637,10 @@ static inline struct tracepoint *tracepoint_ptr_deref= (tracepoint_ptr_t *p) * * * * TP_fast_assign( - * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); + * copy_task_comm(__entry->next_comm, next, TASK_COMM_LEN); * __entry->prev_pid =3D prev->pid; * __entry->prev_prio =3D prev->prio; - * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); + * copy_task_comm(__entry->prev_comm, prev, TASK_COMM_LEN); * __entry->next_pid =3D next->pid; * __entry->next_prio =3D next->prio; * ), diff --git a/include/trace/events/block.h b/include/trace/events/block.h index 9c97a16850b9..1e3a9ded03bd 100644 --- a/include/trace/events/block.h +++ b/include/trace/events/block.h @@ -213,7 +213,7 @@ DECLARE_EVENT_CLASS(block_rq, =20 blk_fill_rwbs(__entry->rwbs, rq->cmd_flags); __get_str(cmd)[0] =3D '\0'; - memcpy(__entry->comm, current->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, current, TASK_COMM_LEN); ), =20 TP_printk("%d,%d %s %u (%s) %llu + %u %s,%u,%u [%s]", @@ -410,7 +410,7 @@ DECLARE_EVENT_CLASS(block_bio, __entry->sector =3D bio->bi_iter.bi_sector; __entry->nr_sector =3D bio_sectors(bio); blk_fill_rwbs(__entry->rwbs, bio->bi_opf); - memcpy(__entry->comm, current->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, current, TASK_COMM_LEN); ), =20 TP_printk("%d,%d %s %llu + %u [%s]", @@ -493,7 +493,7 @@ TRACE_EVENT(block_plug, ), =20 TP_fast_assign( - memcpy(__entry->comm, current->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, current, TASK_COMM_LEN); ), =20 TP_printk("[%s]", __entry->comm) @@ -512,7 +512,7 @@ DECLARE_EVENT_CLASS(block_unplug, =20 TP_fast_assign( __entry->nr_rq =3D depth; - memcpy(__entry->comm, current->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, current, TASK_COMM_LEN); ), =20 TP_printk("[%s] %d", __entry->comm, __entry->nr_rq) @@ -563,7 +563,7 @@ TRACE_EVENT(block_split, __entry->sector =3D bio->bi_iter.bi_sector; __entry->new_sector =3D new_sector; blk_fill_rwbs(__entry->rwbs, bio->bi_opf); - memcpy(__entry->comm, current->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, current, TASK_COMM_LEN); ), =20 TP_printk("%d,%d %s %llu / %llu [%s]", diff --git a/include/trace/events/coredump.h b/include/trace/events/coredum= p.h index c7b9c53fc498..fdd20bc46bb0 100644 --- a/include/trace/events/coredump.h +++ b/include/trace/events/coredump.h @@ -32,7 +32,7 @@ TRACE_EVENT(coredump, =20 TP_fast_assign( __entry->sig =3D sig; - memcpy(__entry->comm, current->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, current, TASK_COMM_LEN); ), =20 TP_printk("sig=3D%d comm=3D%s", diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h index 270c1a2c24c4..7d22650b4c78 100644 --- a/include/trace/events/f2fs.h +++ b/include/trace/events/f2fs.h @@ -2505,7 +2505,7 @@ TRACE_EVENT(f2fs_lock_elapsed_time, =20 TP_fast_assign( __entry->dev =3D sbi->sb->s_dev; - memcpy(__entry->comm, p->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, p, TASK_COMM_LEN); __entry->pid =3D p->pid; __entry->prio =3D p->prio; __entry->ioprio_class =3D IOPRIO_PRIO_CLASS(ioprio); @@ -2558,7 +2558,7 @@ DECLARE_EVENT_CLASS(f2fs_priority_update, =20 TP_fast_assign( __entry->dev =3D sbi->sb->s_dev; - memcpy(__entry->comm, p->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, p, TASK_COMM_LEN); __entry->pid =3D p->pid; __entry->lock_name =3D lock_name; __entry->is_write =3D is_write; diff --git a/include/trace/events/oom.h b/include/trace/events/oom.h index 9f0a5d1482c4..8bcdc4ffc8d3 100644 --- a/include/trace/events/oom.h +++ b/include/trace/events/oom.h @@ -23,7 +23,7 @@ TRACE_EVENT(oom_score_adj_update, =20 TP_fast_assign( __entry->pid =3D task->pid; - memcpy(__entry->comm, task->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, task, TASK_COMM_LEN); __entry->oom_score_adj =3D task->signal->oom_score_adj; ), =20 diff --git a/include/trace/events/osnoise.h b/include/trace/events/osnoise.h index 3f4273623801..2cf047bb9fb7 100644 --- a/include/trace/events/osnoise.h +++ b/include/trace/events/osnoise.h @@ -116,7 +116,7 @@ TRACE_EVENT(thread_noise, ), =20 TP_fast_assign( - memcpy(__entry->comm, t->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, t, TASK_COMM_LEN); __entry->pid =3D t->pid; __entry->start =3D start; __entry->duration =3D duration; diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 535860581f15..afb24e9dac91 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -152,7 +152,7 @@ DECLARE_EVENT_CLASS(sched_wakeup_template, ), =20 TP_fast_assign( - memcpy(__entry->comm, p->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, p, TASK_COMM_LEN); __entry->pid =3D p->pid; __entry->prio =3D p->prio; /* XXX SCHED_DEADLINE */ __entry->target_cpu =3D task_cpu(p); @@ -237,11 +237,11 @@ TRACE_EVENT(sched_switch, ), =20 TP_fast_assign( - memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); + copy_task_comm(__entry->prev_comm, prev, TASK_COMM_LEN); __entry->prev_pid =3D prev->pid; __entry->prev_prio =3D prev->prio; __entry->prev_state =3D __trace_sched_switch_state(preempt, prev_state, = prev); - memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); + copy_task_comm(__entry->next_comm, next, TASK_COMM_LEN); __entry->next_pid =3D next->pid; __entry->next_prio =3D next->prio; /* XXX SCHED_DEADLINE */ @@ -346,7 +346,7 @@ TRACE_EVENT(sched_process_exit, ), =20 TP_fast_assign( - memcpy(__entry->comm, p->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, p, TASK_COMM_LEN); __entry->pid =3D p->pid; __entry->prio =3D p->prio; /* XXX SCHED_DEADLINE */ __entry->group_dead =3D group_dead; @@ -787,7 +787,7 @@ TRACE_EVENT(sched_skip_cpuset_numa, ), =20 TP_fast_assign( - memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, tsk, TASK_COMM_LEN); __entry->pid =3D task_pid_nr(tsk); __entry->tgid =3D task_tgid_nr(tsk); __entry->ngid =3D task_numa_group_id(tsk); diff --git a/include/trace/events/signal.h b/include/trace/events/signal.h index 1db7e4b07c01..8fffe6d9bdcc 100644 --- a/include/trace/events/signal.h +++ b/include/trace/events/signal.h @@ -67,7 +67,7 @@ TRACE_EVENT(signal_generate, TP_fast_assign( __entry->sig =3D sig; TP_STORE_SIGINFO(__entry, info); - memcpy(__entry->comm, task->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, task, TASK_COMM_LEN); __entry->pid =3D task->pid; __entry->group =3D group; __entry->result =3D result; diff --git a/include/trace/events/task.h b/include/trace/events/task.h index b9a129eb54d9..62b7df4d22d0 100644 --- a/include/trace/events/task.h +++ b/include/trace/events/task.h @@ -21,7 +21,7 @@ TRACE_EVENT(task_newtask, =20 TP_fast_assign( __entry->pid =3D task->pid; - memcpy(__entry->comm, task->comm, TASK_COMM_LEN); + copy_task_comm(__entry->comm, task, TASK_COMM_LEN); __entry->clone_flags =3D clone_flags; __entry->oom_score_adj =3D task->signal->oom_score_adj; ), @@ -46,8 +46,9 @@ TRACE_EVENT(task_rename, =20 TP_fast_assign( __entry->pid =3D task->pid; - memcpy(entry->oldcomm, task->comm, TASK_COMM_LEN); - strscpy(entry->newcomm, comm, TASK_COMM_LEN); + copy_task_comm(entry->oldcomm, task, TASK_COMM_LEN); + memcpy(entry->newcomm, comm, TASK_COMM_LEN); + entry->newcomm[TASK_COMM_LEN - 1] =3D '\0'; __entry->oom_score_adj =3D task->signal->oom_score_adj; ), =20 diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c index 4b03b019cd5e..f4c5ae8a3530 100644 --- a/kernel/printk/nbcon.c +++ b/kernel/printk/nbcon.c @@ -952,7 +952,7 @@ static void wctxt_load_execution_ctx(struct nbcon_write= _context *wctxt, { wctxt->cpu =3D pmsg->cpu; wctxt->pid =3D pmsg->pid; - memcpy(wctxt->comm, pmsg->comm, sizeof(wctxt->comm)); + copy_task_comm(wctxt->comm, pmsg, sizeof(wctxt->comm)); static_assert(sizeof(wctxt->comm) =3D=3D sizeof(pmsg->comm)); } #else diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 019b11de262c..ec0c6734bbe1 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2255,7 +2255,7 @@ static void pmsg_load_execution_ctx(struct printk_mes= sage *pmsg, { pmsg->cpu =3D printk_info_get_cpu(info); pmsg->pid =3D printk_info_get_pid(info); - memcpy(pmsg->comm, info->comm, sizeof(pmsg->comm)); + copy_task_comm(pmsg->comm, info, sizeof(pmsg->comm)); static_assert(sizeof(pmsg->comm) =3D=3D sizeof(info->comm)); 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Check if a copy from a task_struct works, and special cases when the size of source and destination buffer mismatches. Signed-off-by: Andr=C3=A9 Almeida --- lib/tests/string_kunit.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c index 0819ace5b027..b64d7f0e54a3 100644 --- a/lib/tests/string_kunit.c +++ b/lib/tests/string_kunit.c @@ -881,6 +881,43 @@ static void string_bench_strrchr(struct kunit *test) STRING_BENCH_BUF(test, buf, len, strrchr, buf, '\0'); } =20 +#define TASK_NAME "task_name" +#define TASK_NAME_LEN 9 +#define TASK_MAX_LEN TASK_COMM_LEN +#define SMALLER_LEN TASK_NAME_LEN - 3 +#define BIGGER_LEN TASK_MAX_LEN + 3 + +static void string_copy_task_comm(struct kunit *test) +{ + char str[TASK_MAX_LEN] =3D TASK_NAME, copy[TASK_MAX_LEN], + smaller_buf[SMALLER_LEN], bigger_buf[BIGGER_LEN]; + static struct task_struct task, *tsk =3D &task; + int len1, len2, i; + + /* set and get task name */ + set_task_comm(tsk, str); + copy_task_comm(copy, tsk, TASK_COMM_LEN); + + len1 =3D strlen(str); + len2 =3D strlen(copy); + + KUNIT_ASSERT_EQ(test, len1, len2); + KUNIT_ASSERT_EQ(test, len2, TASK_NAME_LEN); + KUNIT_ASSERT_EQ(test, copy[len2], '\0'); + KUNIT_ASSERT_TRUE(test, !strcmp(str, copy)); + + /* copy to a smaller dst buffer */ + copy_task_comm(smaller_buf, tsk, sizeof(smaller_buf)); + KUNIT_ASSERT_TRUE(test, !strncmp(str, smaller_buf, SMALLER_LEN - 1)); + KUNIT_ASSERT_EQ(test, smaller_buf[SMALLER_LEN - 1], '\0'); + + /* copy to a bigger dst buffer */ + copy_task_comm(bigger_buf, tsk, sizeof(bigger_buf)); + KUNIT_ASSERT_TRUE(test, !strncmp(str, bigger_buf, TASK_NAME_LEN)); + for (i =3D TASK_NAME_LEN; i < BIGGER_LEN; i++) + KUNIT_ASSERT_EQ(test, bigger_buf[i], '\0'); +} + static struct kunit_case string_test_cases[] =3D { KUNIT_CASE(string_test_memset16), KUNIT_CASE(string_test_memset32), @@ -910,6 +947,7 @@ static struct kunit_case string_test_cases[] =3D { KUNIT_CASE(string_bench_strnlen), KUNIT_CASE(string_bench_strchr), KUNIT_CASE(string_bench_strrchr), + KUNIT_CASE(string_copy_task_comm), {} }; 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Received: from [179.118.191.219] (helo=[192.168.15.100]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1wkj25-00GXeM-Gq; Fri, 17 Jul 2026 15:55:17 +0200 From: =?utf-8?q?Andr=C3=A9_Almeida?= Date: Fri, 17 Jul 2026 10:54:37 -0300 Subject: [PATCH v4 4/6] sched: Extend task command name with TASK_COMM_EXT_LEN Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260717-tonyk-long_name-v4-4-1fedfc870d21@igalia.com> References: <20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com> In-Reply-To: <20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com> To: Peter Zijlstra , Juri Lelli , Vincent Guittot , Steven Rostedt , Christian Brauner , Kees Cook , Shuah Khan , willy@infradead.org, mathieu.desnoyers@efficios.com, David Laight , Linus Torvalds , akpm@linux-foundation.org, Yafang Shao , andrii.nakryiko@gmail.com, arnaldo.melo@gmail.com, Petr Mladek Cc: linux-kernel@vger.kernel.org, kernel-dev@igalia.com, linux-mm@kvack.org, linux-api@vger.kernel.org, =?utf-8?q?Andr=C3=A9_Almeida?= X-Mailer: b4 0.15.2 Command name has been restrict to only 16 bytes, which is too limiting, specially when debugging and tracing complex software with thousands of threads and the need to differentiate them. Just as it was done with kthreads in commit 6b59808bfe48 ("workqueue: Show the latest workqueue name in /proc/PID/{comm,stat,status}"), support long names for userspace threads as well. To avoid buffer overflows, cap all existing userspace APIs to TASK_COMM_LEN, and leave the full extended name for a new interface. Signed-off-by: Andr=C3=A9 Almeida --- fs/proc/array.c | 2 +- include/linux/sched.h | 3 ++- kernel/sys.c | 10 +++++----- lib/tests/string_kunit.c | 2 +- 4 files changed, 9 insertions(+), 8 deletions(-) diff --git a/fs/proc/array.c b/fs/proc/array.c index 905d910b598f..0490b9ef2788 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -110,7 +110,7 @@ void proc_task_name(struct seq_file *m, struct task_str= uct *p, bool escape) else if (p->flags & PF_KTHREAD) get_kthread_comm(tcomm, sizeof(tcomm), p); else - strscpy_pad(tcomm, p->comm); + strscpy_pad(tcomm, p->comm, TASK_COMM_LEN); =20 if (escape) seq_escape_str(m, tcomm, ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\"); diff --git a/include/linux/sched.h b/include/linux/sched.h index 9b6a413f6618..6a48517f01cc 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -323,6 +323,7 @@ struct user_event_mm; */ enum { TASK_COMM_LEN =3D 16, + TASK_COMM_EXT_LEN =3D 64, }; =20 extern void sched_tick(void); @@ -1178,7 +1179,7 @@ struct task_struct { * - set it with set_task_comm() to ensure it is always * NUL-terminated and zero-padded */ - char comm[TASK_COMM_LEN]; + char comm[TASK_COMM_EXT_LEN]; =20 struct nameidata *nameidata; =20 diff --git a/kernel/sys.c b/kernel/sys.c index 74c22d6dded0..3c37b5c1c072 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2535,7 +2535,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, ar= g2, unsigned long, arg3, unsigned long, arg4, unsigned long, arg5) { struct task_struct *me =3D current; - unsigned char comm[sizeof(me->comm)]; + unsigned char comm[TASK_COMM_LEN]; long error; =20 error =3D security_task_prctl(option, arg2, arg3, arg4, arg5); @@ -2601,16 +2601,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, = arg2, unsigned long, arg3, error =3D -EINVAL; break; case PR_SET_NAME: - comm[sizeof(me->comm) - 1] =3D 0; + comm[TASK_COMM_LEN - 1] =3D 0; if (strncpy_from_user(comm, (char __user *)arg2, - sizeof(me->comm) - 1) < 0) + TASK_COMM_LEN - 1) < 0) return -EFAULT; set_task_comm(me, comm); proc_comm_connector(me); break; case PR_GET_NAME: - strscpy_pad(comm, me->comm); - if (copy_to_user((char __user *)arg2, comm, sizeof(comm))) + strscpy_pad(comm, me->comm, TASK_COMM_LEN); + if (copy_to_user((char __user *)arg2, comm, TASK_COMM_LEN)) return -EFAULT; break; case PR_GET_ENDIAN: diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c index b64d7f0e54a3..5d26029d2d01 100644 --- a/lib/tests/string_kunit.c +++ b/lib/tests/string_kunit.c @@ -883,7 +883,7 @@ static void string_bench_strrchr(struct kunit *test) =20 #define TASK_NAME "task_name" #define TASK_NAME_LEN 9 -#define TASK_MAX_LEN TASK_COMM_LEN +#define TASK_MAX_LEN TASK_COMM_EXT_LEN #define SMALLER_LEN TASK_NAME_LEN - 3 #define BIGGER_LEN TASK_MAX_LEN + 3 =20 --=20 2.55.0 From nobody Sat Jul 25 05:28:14 2026 Received: from fanzine2.igalia.com (fanzine2.igalia.com [213.97.179.56]) (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 6A244417D8D; Fri, 17 Jul 2026 13:55:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.97.179.56 ARC-Seal: i=1; a=rsa-sha256; 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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260717-tonyk-long_name-v4-5-1fedfc870d21@igalia.com> References: <20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com> In-Reply-To: <20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com> To: Peter Zijlstra , Juri Lelli , Vincent Guittot , Steven Rostedt , Christian Brauner , Kees Cook , Shuah Khan , willy@infradead.org, mathieu.desnoyers@efficios.com, David Laight , Linus Torvalds , akpm@linux-foundation.org, Yafang Shao , andrii.nakryiko@gmail.com, arnaldo.melo@gmail.com, Petr Mladek Cc: linux-kernel@vger.kernel.org, kernel-dev@igalia.com, linux-mm@kvack.org, linux-api@vger.kernel.org, =?utf-8?q?Andr=C3=A9_Almeida?= X-Mailer: b4 0.15.2 Add support for getting and setting long user thread names with PR_{SET,GET}_EXT_NAME. Signed-off-by: Andr=C3=A9 Almeida --- include/linux/sched.h | 2 +- include/uapi/linux/prctl.h | 3 +++ kernel/sys.c | 15 ++++++++++++++- 3 files changed, 18 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 6a48517f01cc..0f1b40a5dbc6 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2018,7 +2018,7 @@ extern void kick_process(struct task_struct *tsk); =20 extern void __set_task_comm(struct task_struct *tsk, const char *from, boo= l exec); #define set_task_comm(tsk, from) ({ \ - BUILD_BUG_ON(sizeof(from) !=3D TASK_COMM_LEN); \ + BUILD_BUG_ON(sizeof(from) < TASK_COMM_LEN); \ __set_task_comm(tsk, from, false); \ }) =20 diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index b6ec6f693719..a07f8edadd65 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -56,6 +56,9 @@ #define PR_SET_NAME 15 /* Set process name */ #define PR_GET_NAME 16 /* Get process name */ =20 +#define PR_SET_EXT_NAME 17 /* Set extended process name */ +#define PR_GET_EXT_NAME 18 /* Get extended process name */ + /* Get/set process endian */ #define PR_GET_ENDIAN 19 #define PR_SET_ENDIAN 20 diff --git a/kernel/sys.c b/kernel/sys.c index 3c37b5c1c072..26d5026f9590 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2535,7 +2535,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, ar= g2, unsigned long, arg3, unsigned long, arg4, unsigned long, arg5) { struct task_struct *me =3D current; - unsigned char comm[TASK_COMM_LEN]; + unsigned char comm[TASK_COMM_EXT_LEN]; long error; =20 error =3D security_task_prctl(option, arg2, arg3, arg4, arg5); @@ -2613,6 +2613,19 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, a= rg2, unsigned long, arg3, if (copy_to_user((char __user *)arg2, comm, TASK_COMM_LEN)) return -EFAULT; break; + case PR_SET_EXT_NAME: + comm[TASK_COMM_EXT_LEN - 1] =3D 0; + if (strncpy_from_user(comm, (char __user *)arg2, + TASK_COMM_EXT_LEN - 1) < 0) + return -EFAULT; + set_task_comm(me, comm); + proc_comm_connector(me); + break; + case PR_GET_EXT_NAME: + strscpy_pad(comm, me->comm, TASK_COMM_EXT_LEN); + if (copy_to_user((char __user *)arg2, comm, TASK_COMM_EXT_LEN)) + return -EFAULT; + break; case PR_GET_ENDIAN: error =3D GET_ENDIAN(me, arg2); break; --=20 2.55.0 From nobody Sat Jul 25 05:28:14 2026 Received: from fanzine2.igalia.com (fanzine2.igalia.com [213.97.179.56]) (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 231F0417D76; 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Fri, 17 Jul 2026 15:55:27 +0200 From: =?utf-8?q?Andr=C3=A9_Almeida?= Date: Fri, 17 Jul 2026 10:54:39 -0300 Subject: [PATCH v4 6/6] selftests: prctl: Add test for long thread names Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260717-tonyk-long_name-v4-6-1fedfc870d21@igalia.com> References: <20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com> In-Reply-To: <20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com> To: Peter Zijlstra , Juri Lelli , Vincent Guittot , Steven Rostedt , Christian Brauner , Kees Cook , Shuah Khan , willy@infradead.org, mathieu.desnoyers@efficios.com, David Laight , Linus Torvalds , akpm@linux-foundation.org, Yafang Shao , andrii.nakryiko@gmail.com, arnaldo.melo@gmail.com, Petr Mladek Cc: linux-kernel@vger.kernel.org, kernel-dev@igalia.com, linux-mm@kvack.org, linux-api@vger.kernel.org, =?utf-8?q?Andr=C3=A9_Almeida?= X-Mailer: b4 0.15.2 Add tests for the new interface to set and get long thread names. The kernel should accept the LONG_NAME and returning it accordingly. For the old PR_GET_NAME interface, the kernel should truncate the name up to 16 chars. /proc//comm should return the same string ad PR_GET_NAME. Signed-off-by: Andr=C3=A9 Almeida --- tools/testing/selftests/prctl/set-process-name.c | 36 ++++++++++++++++++++= ++++ 1 file changed, 36 insertions(+) diff --git a/tools/testing/selftests/prctl/set-process-name.c b/tools/testi= ng/selftests/prctl/set-process-name.c index 3f7b146d36df..0f20f7deac67 100644 --- a/tools/testing/selftests/prctl/set-process-name.c +++ b/tools/testing/selftests/prctl/set-process-name.c @@ -9,9 +9,17 @@ =20 #include "kselftest_harness.h" =20 +#ifndef PR_SET_EXT_NAME +# define PR_SET_EXT_NAME 17 +# define PR_GET_EXT_NAME 18 +#endif + #define CHANGE_NAME "changename" +#define LONG_NAME "change_to_very_long_extended_name" +#define LONG_NAME_CAP "change_to_very_" #define EMPTY_NAME "" #define TASK_COMM_LEN 16 +#define TASK_COMM_EXT_LEN 64 #define MAX_PATH_LEN 50 =20 int set_name(char *name) @@ -25,6 +33,16 @@ int set_name(char *name) return res; } =20 +int set_ext_name(char *name) +{ + int res; + + res =3D prctl(PR_SET_EXT_NAME, name, NULL, NULL, NULL); + + if (res < 0) + return -errno; +} + int check_is_name_correct(char *check_name) { char name[TASK_COMM_LEN]; @@ -38,6 +56,19 @@ int check_is_name_correct(char *check_name) return !strcmp(name, check_name); } =20 +int check_is_ext_name_correct(char *check_name) +{ + char name[TASK_COMM_EXT_LEN]; + int res; + + res =3D prctl(PR_GET_EXT_NAME, name, NULL, NULL, NULL); + + if (res < 0) + return -errno; + + return !strcmp(name, check_name); +} + int check_null_pointer(char *check_name) { char *name =3D NULL; @@ -82,6 +113,11 @@ TEST(rename_process) { EXPECT_GE(set_name(CHANGE_NAME), 0); EXPECT_TRUE(check_is_name_correct(CHANGE_NAME)); =20 + EXPECT_GE(set_ext_name(LONG_NAME), 0); + EXPECT_TRUE(check_is_ext_name_correct(LONG_NAME)); + EXPECT_TRUE(check_is_name_correct(LONG_NAME_CAP)); + EXPECT_TRUE(check_name()); + EXPECT_GE(set_name(EMPTY_NAME), 0); EXPECT_TRUE(check_is_name_correct(EMPTY_NAME)); =20 --=20 2.55.0