From mboxrd@z Thu Jan 1 00:00:00 1970 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 48CC61FC0; Thu, 27 Aug 2026 18:23:41 +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=1787855025; cv=none; b=PuNVZxRyEh04RJiilspv0hxXavQlZxXupj8MEplopuToXv5JUdf6sJi6+V13X6yENs3VUl4mFKktLtDrw5T+cVWHPlpPkqNUDVh5eo1OjZ2MKBUaWU46jui4O9c9osHNeggH8EXV2kGj4rgExwrVIZyoMQtryvfweFMLXRyh23E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787855025; c=relaxed/simple; bh=NTpk/J9rpNjetJmd6pVzwIlDZyZF8zY2ytNk++SopB4=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=C2qpQyNFzYucNmTYZ68nim/NXeW4Zu0L4XVNTe8HEMAZGhkbAItYTleRTeqLScWRZWWgZWVEV7OlCtraP29dHZPXYIlowuIdfjEJi1HsFicI8FV2JN8GrcWlREDgjDS0qvo69wN04OXnDtUcl1+TYfStGZ1hnsZOeuv6DsEDrcs= 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=ss+YEE4b; 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="ss+YEE4b" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Cc:To:Content-Transfer-Encoding:Content-Type:MIME-Version: Message-Id:Date:Subject:From:From:Reply-To; bh=lW5yUPVESWNp8FJ60ucl8RG8n/LJobsXvM0l0Jreta8=; b=ss+YEE4b/aZyxI4zRVBqSur/8v Fc85AUt8epJqduW4+yRAI2hbrSKRfL+YgA+hpmpTYZqKe4LY2lA60lulc4/I8/XwchM0EgOxcuOu+ kO09vhl3rg/Dyg3xzRfrsnZ+eU6HE5ZWP08df2XhtDekUWbiQoC/71/llCxH0K64Zp3oidfGsRxqQ cPa9x3aRlEkQSEtb+pWKH6Z2S8WIPdEtL/a08HrMFp7cj/M6fZq2yN8JTpfeCsNl/7ItPOh8PBPea mO2Y7aDq+4DeQTU4FjpaPnX51CfSaxcUTQjwxG0jtU4t6rTTYkBTUcK90srBFdeLweMm3Up721GTk VDY+LmmA==; Received: from [187.57.78.212] (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 1wzekx-00AOUg-3S; Thu, 27 Aug 2026 20:23:19 +0200 From: =?utf-8?q?Andr=C3=A9_Almeida?= Subject: [PATCH v5 0/6] sched: Add support for long task name Date: Thu, 27 Aug 2026 15:22:59 -0300 Message-Id: <20260827-tonyk-long_name-v5-0-5fa843782a00@igalia.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-B4-Tracking: v=1; b=H4sIAAAAAAAC/23P0U4DIRAF0F9peBYDA8suPvkfpjHADlu0BbNsN zbN/rtQY6rBx5vcOTNzJRnngJk87a5kxjXkkGIJ3cOOuIOJE9IwlkyAgWIdV3RJ8fJOjylOr9G ckFrthewMWiY5KVMfM/rweRNf9t85n+0buqUytXEIeUnz5bZy5bX3o/eNvnLKqHAwABqjOcJzm MwxmEeXTqTyK/wCQLYAVECAV3YsFzrZAOIOKA4tIArQ60FbpXAwWjeAvAP9fy/IAnCPo3dDz0b gf4Bt274AOov+54QBAAA= X-Change-ID: 20260516-tonyk-long_name-b9f345aeb041 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, linux-trace-kernel@vger.kernel.org, =?utf-8?q?Andr=C3=A9_Almeida?= X-Mailer: b4 0.15.2 * Use case When debugging and tracing complex programs with hundreds of threads, 16 bytes long thread names are not enough anymore. cmd_line can show a lot of characters, but it's not affected by pthread_setname_np() or prctl(PR_SET_NAME), so let's give the same love kthreads got with commit 6b59808bfe48 ("workqueue: Show the latest workqueue name in /proc/PID/{comm,stat,status}"). This patchset creates a new PR_{SET,GET}_EXT_NAME that supports 64 bytes long names. It also introduces a new function copy_task_comm() that ensures that the string is always NUL-terminated despite of mismatching sizes of buffers. We can't just use strscpy() because it proved to give some overhead [0] in tracing. * Patchset Patch 1 and 2 do some prep work in order to avoid buffer overflows around the kernel, now that current->comm is bigger. It also make sure that if the destination buffer is smaller than TASK_COMM_EXT_LEN, it will be NUL-terminated. Patch 3 adds a KUnit for the new function copy_task_comm() Patch 4 sets current->comm length to TASK_COMM_EXT_LEN and take care of making sure that current userspace APIs gets only TASK_COMM_LEN. Patch 5 creates new prctl() to set and get all the TASK_COMM_EXT_LEN bytes. Patch 6 adapts the existing selftest for this new interface. * Testing selftests/prctl/set-process-name.c survives this patchset, and it was extended to the new interface. KUnit test was modified to support copy_task_comm(). I ran the same benchmark as at [0], and no significant change was found. * Changes Since v4: - Remove copy_task_comm() calls for structs other than struct task_struct - copy_task_comm(): Add checks for len > TASK_COMM_LEN and len < 0 - Link to v4: https://patch.msgid.link/20260717-tonyk-long_name-v4-0-1fedfc870d21@igalia.com Since v3: - Simplify Get rid of get_task_comm() commit - Simplify copy_task_comm(): just do a memcpy + NUL char at the end - Link to v3: https://patch.msgid.link/20260612-tonyk-long_name-v3-0-7989b66e8a99@igalia.com Since v2: - Add a custom function copy_task_comm() that uses memcpy when possible and fallback to strscpy(). It always ensures that the string in NUL-terminated - Add KUnit test for the new function - Link to v2: https://patch.msgid.link/20260524-tonyk-long_name-v2-0-332f6bd041c4@igalia.com Since v1: - Replace new strtostr() with strscpy() - Don't replace memcpy in tools/ - Link to v1: https://patch.msgid.link/20260517-tonyk-long_name-v1-0-3c282eaa91e2@igalia.com [0] https://lore.kernel.org/lkml/20260526190625.3f4aca0a@gandalf.local.home/ --- André Almeida (6): treewide: Get rid of get_task_comm() treewide: Replace memcpy(..., current->comm) with copy_task_comm() lib/string_kunit: Add test for copy_task_comm() sched: Extend task command name with TASK_COMM_EXT_LEN prctl: Add support for long user thread names selftests: prctl: Add test for long thread names 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/coredump.h | 2 +- include/linux/sched.h | 33 +++++++++---------- 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 | 4 +-- include/uapi/linux/prctl.h | 3 ++ kernel/audit.c | 6 ++-- kernel/auditsc.c | 6 ++-- kernel/printk/printk.c | 2 +- kernel/sys.c | 23 ++++++++++--- lib/tests/string_kunit.c | 38 ++++++++++++++++++++++ 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 ++-- tools/testing/selftests/prctl/set-process-name.c | 37 +++++++++++++++++++++ 42 files changed, 173 insertions(+), 76 deletions(-) --- base-commit: 73e3f0710014fe6d4ed98cfc02292f6121db7558 change-id: 20260516-tonyk-long_name-b9f345aeb041 Best regards, -- André Almeida