From patchwork Mon Nov 1 06:04:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12595815 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6A29C433F5 for ; Mon, 1 Nov 2021 06:04:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 940426108D for ; Mon, 1 Nov 2021 06:04:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230329AbhKAGHI (ORCPT ); Mon, 1 Nov 2021 02:07:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55200 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230096AbhKAGHF (ORCPT ); Mon, 1 Nov 2021 02:07:05 -0400 Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3937FC061714; Sun, 31 Oct 2021 23:04:32 -0700 (PDT) Received: by mail-pj1-x102b.google.com with SMTP id y14-20020a17090a2b4e00b001a5824f4918so8469706pjc.4; Sun, 31 Oct 2021 23:04:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=jvb/C5XEaJIeXrLXfpoEk1LkH8WdHTYd7IpTBiq7fdU=; b=QzDoHhHVbtF/bMpHfWbGSlGfWhrLJ3uom/bYNboWDxPau83NZSUbxcsyS3VC0UFwNm IYFWwZxp+p4qvZ5D2tK0osULt9fSRrn39+6+qRP+w8MHRqyPsENAX3Qbce93XloeW0b7 bhZt0u3DwNeykH6ljwHZncNhJdpGAHRDhJ+vIJ5DBB7n6lBWqcVSVnF3oo2IyGW0E2kq JGcTLy1m5V0sKMiuH0G7VtSf8DXS60yNBtgOiW7rsb0a+93/1HmKSOD1N4EI+UEMmIzY d2ig8smuUy3ycMA8HdA6saon+W6X9JZ04Wu2GeG9I6XPzrEbZl3+/fmY4uZ51gpf30GP lfVA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=jvb/C5XEaJIeXrLXfpoEk1LkH8WdHTYd7IpTBiq7fdU=; b=plSWlPFiegA4DXLYdGmQ8H80+yBa1zLZs5rjg3FgYMVG7uI/I22dj0ai88yHMtoafA OvjuS3vqLgDqYGJPmI8DsvvOr+qnQRRTSYI7+DfNYDu7TwTOu5zYOQW3bS3q3mxGY3cp SzRB/gBgwgW88o24spqvA4dmT+cgq4ojjfUPfSKi9xeXKgthMBRiUNoWbVAX3RJmOuj5 UMXE/M8LnTCjCScjI9vCzRstnG/4HQxwoCEfT7ODUa6A7PIvhMuD0Ldd/V3cEtyUSk2X aHtujJJntasDmcvHeMKOJXgeQRBwAcxeRvLGngS0BoNpgr9iehD8T2HUKQrkuczkOjC8 fsLA== X-Gm-Message-State: AOAM532768AUKzgzYetxW2Z0V7SgcOKFGlJFScaVAf7Ixfx7NmWJCcpV iw+cK9IeclNM6PvuJGC3HzI= X-Google-Smtp-Source: ABdhPJz8UISjP4gb7nXyp0XisjyBJXUE5NhjaTe21LGX2ejW8wzAuI9dQOwUx1G/kySMdPO2jta5Ag== X-Received: by 2002:a17:90b:30c6:: with SMTP id hi6mr16797530pjb.201.1635746671810; Sun, 31 Oct 2021 23:04:31 -0700 (PDT) Received: from localhost.localdomain ([144.202.123.152]) by smtp.gmail.com with ESMTPSA id g8sm3277586pfc.65.2021.10.31.23.04.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Oct 2021 23:04:31 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Alexei Starovoitov , Andrii Nakryiko Subject: [PATCH v7 01/11] fs/exec: make __set_task_comm always set a nul terminated string Date: Mon, 1 Nov 2021 06:04:09 +0000 Message-Id: <20211101060419.4682-2-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Make sure the string set to task comm is always nul terminated. Signed-off-by: Yafang Shao Reviewed-by: Kees Cook Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek --- fs/exec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/exec.c b/fs/exec.c index a098c133d8d7..404156b5b314 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1224,7 +1224,7 @@ void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) { task_lock(tsk); trace_task_rename(tsk, buf); - strlcpy(tsk->comm, buf, sizeof(tsk->comm)); + strscpy_pad(tsk->comm, buf, sizeof(tsk->comm)); task_unlock(tsk); perf_event_comm(tsk, exec); } From patchwork Mon Nov 1 06:04:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12595817 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 212FAC433FE for ; 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Sun, 31 Oct 2021 23:04:34 -0700 (PDT) Received: from localhost.localdomain ([144.202.123.152]) by smtp.gmail.com with ESMTPSA id g8sm3277586pfc.65.2021.10.31.23.04.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Oct 2021 23:04:33 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Alexei Starovoitov , Andrii Nakryiko Subject: [PATCH v7 02/11] fs/exec: make __get_task_comm always get a nul terminated string Date: Mon, 1 Nov 2021 06:04:10 +0000 Message-Id: <20211101060419.4682-3-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org If the dest buffer size is smaller than sizeof(tsk->comm), the buffer will be without null ternimator, that may cause problem. We can make sure the buffer size not smaller than comm at the callsite to avoid that problem, but there may be callsite that we can't easily change. Using strscpy_pad() instead of strncpy() in __get_task_comm() can make the string always nul ternimated. Suggested-by: Kees Cook Suggested-by: Steven Rostedt Signed-off-by: Yafang Shao Reviewed-by: Kees Cook Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek --- fs/exec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/exec.c b/fs/exec.c index 404156b5b314..013b707d995d 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1209,7 +1209,8 @@ static int unshare_sighand(struct task_struct *me) char *__get_task_comm(char *buf, size_t buf_size, struct task_struct *tsk) { task_lock(tsk); - strncpy(buf, tsk->comm, buf_size); + /* Always NUL terminated and zero-padded */ + strscpy_pad(buf, tsk->comm, buf_size); task_unlock(tsk); return buf; } From patchwork Mon Nov 1 06:04:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12595819 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8FDECC4332F for ; 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Sun, 31 Oct 2021 23:04:36 -0700 (PDT) Received: from localhost.localdomain ([144.202.123.152]) by smtp.gmail.com with ESMTPSA id g8sm3277586pfc.65.2021.10.31.23.04.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Oct 2021 23:04:35 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Alexei Starovoitov , Andrii Nakryiko Subject: [PATCH v7 03/11] sched.h: use __must_be_array instead of BUILD_BUG_ON in get_task_comm Date: Mon, 1 Nov 2021 06:04:11 +0000 Message-Id: <20211101060419.4682-4-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Now that __get_task_comm() will truncate and pad, it's safe to use on both too-small and too-big arrays. So it is not needed to check array length any more. For the original goal of making sure get_task_comm() is being used on a char array, we can use __must_be_array(). Below is the verification when I changed the dest buffer of get_task_comm() in a driver code, CC [M] drivers/infiniband/hw/qib/qib_file_ops.o In file included from ./include/linux/bits.h:22:0, from ./include/linux/ioport.h:13, from ./include/linux/pci.h:31, from drivers/infiniband/hw/qib/qib_file_ops.c:35: drivers/infiniband/hw/qib/qib_file_ops.c: In function ‘setup_ctxt’: ./include/linux/build_bug.h:16:51: error: negative width in bit-field ‘’ #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); }))) ^ ./include/linux/compiler.h:258:28: note: in expansion of macro ‘BUILD_BUG_ON_ZERO’ #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) ^~~~~~~~~~~~~~~~~ ./include/linux/sched.h:1941:23: note: in expansion of macro ‘__must_be_array’ __get_task_comm(buf, __must_be_array(buf) + sizeof(buf), tsk) ^~~~~~~~~~~~~~~ drivers/infiniband/hw/qib/qib_file_ops.c:1325:2: note: in expansion of macro ‘get_task_comm’ get_task_comm(test, current); It hit this warnig as expected. Suggested-by: Kees Cook Signed-off-by: Yafang Shao Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek --- include/linux/sched.h | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index c1a927ddec64..b9c85c52fed0 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1931,10 +1931,8 @@ static inline void set_task_comm(struct task_struct *tsk, const char *from) } extern char *__get_task_comm(char *to, size_t len, struct task_struct *tsk); -#define get_task_comm(buf, tsk) ({ \ - BUILD_BUG_ON(sizeof(buf) != TASK_COMM_LEN); \ - __get_task_comm(buf, sizeof(buf), tsk); \ -}) +#define get_task_comm(buf, tsk) \ + __get_task_comm(buf, __must_be_array(buf) + sizeof(buf), tsk) #ifdef CONFIG_SMP static __always_inline void scheduler_ipi(void) From patchwork Mon Nov 1 06:04:12 2021 Content-Type: text/plain; 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Sun, 31 Oct 2021 23:04:38 -0700 (PDT) Received: from localhost.localdomain ([144.202.123.152]) by smtp.gmail.com with ESMTPSA id g8sm3277586pfc.65.2021.10.31.23.04.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Oct 2021 23:04:38 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Alexei Starovoitov , Andrii Nakryiko Subject: [PATCH v7 04/11] drivers/infiniband: make setup_ctxt always get a nul terminated task comm Date: Mon, 1 Nov 2021 06:04:12 +0000 Message-Id: <20211101060419.4682-5-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Use get_task_comm() instead of open-coded strlcpy() to make the comm always nul terminated. As the comment above the hard-coded 16, we can replace it with TASK_COMM_LEN, then it will adopt to the comm size change. Signed-off-by: Yafang Shao Acked-by: Dennis Dalessandro Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek --- drivers/infiniband/hw/qib/qib.h | 2 +- drivers/infiniband/hw/qib/qib_file_ops.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/hw/qib/qib.h b/drivers/infiniband/hw/qib/qib.h index 9363bccfc6e7..a8e1c30c370f 100644 --- a/drivers/infiniband/hw/qib/qib.h +++ b/drivers/infiniband/hw/qib/qib.h @@ -196,7 +196,7 @@ struct qib_ctxtdata { pid_t pid; pid_t subpid[QLOGIC_IB_MAX_SUBCTXT]; /* same size as task_struct .comm[], command that opened context */ - char comm[16]; + char comm[TASK_COMM_LEN]; /* pkeys set by this use of this ctxt */ u16 pkeys[4]; /* so file ops can get at unit */ diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c index 63854f4b6524..aa290928cf96 100644 --- a/drivers/infiniband/hw/qib/qib_file_ops.c +++ b/drivers/infiniband/hw/qib/qib_file_ops.c @@ -1321,7 +1321,7 @@ static int setup_ctxt(struct qib_pportdata *ppd, int ctxt, rcd->tid_pg_list = ptmp; rcd->pid = current->pid; init_waitqueue_head(&dd->rcd[ctxt]->wait); - strlcpy(rcd->comm, current->comm, sizeof(rcd->comm)); + get_task_comm(rcd->comm, current); ctxt_fp(fp) = rcd; qib_stats.sps_ctxts++; dd->freectxts--; From patchwork Mon Nov 1 06:04:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12595823 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D76AFC433EF for ; Mon, 1 Nov 2021 06:05:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFC8661078 for ; Mon, 1 Nov 2021 06:05:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231147AbhKAGHs (ORCPT ); Mon, 1 Nov 2021 02:07:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231138AbhKAGHO (ORCPT ); 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Sun, 31 Oct 2021 23:04:40 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Andrii Nakryiko Subject: [PATCH v7 05/11] fs/binfmt_elf: make prpsinfo always get a nul terminated task comm Date: Mon, 1 Nov 2021 06:04:13 +0000 Message-Id: <20211101060419.4682-6-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org kernel test robot reported a -Wstringop-truncation warning after I extend task comm from 16 to 24. Below is the detailed warning: fs/binfmt_elf.c: In function 'fill_psinfo.isra': >> fs/binfmt_elf.c:1575:9: warning: 'strncpy' output may be truncated copying 16 bytes from a string of length 23 [-Wstringop-truncation] 1575 | strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Replacing the open-coded strncpy() with the helper get_task_comm() can avoid this warning. As the struct prpsinfo is externally parsed, for example by the crash utility, we can't change the size of pr_fname. So I just leave it as-is. I also verfied if it still work well when I extend the comm size to 24. struct elf_prpsinfo is used to dump the task information in userspace coredump or kernel vmcore. Below is the verfication of vmcore, crash> ps PID PPID CPU TASK ST %MEM VSZ RSS COMM 0 0 0 ffffffff9d21a940 RU 0.0 0 0 [swapper/0] > 0 0 1 ffffa09e40f85e80 RU 0.0 0 0 [swapper/1] > 0 0 2 ffffa09e40f81f80 RU 0.0 0 0 [swapper/2] > 0 0 3 ffffa09e40f83f00 RU 0.0 0 0 [swapper/3] > 0 0 4 ffffa09e40f80000 RU 0.0 0 0 [swapper/4] > 0 0 5 ffffa09e40f89f80 RU 0.0 0 0 [swapper/5] 0 0 6 ffffa09e40f8bf00 RU 0.0 0 0 [swapper/6] > 0 0 7 ffffa09e40f88000 RU 0.0 0 0 [swapper/7] > 0 0 8 ffffa09e40f8de80 RU 0.0 0 0 [swapper/8] > 0 0 9 ffffa09e40f95e80 RU 0.0 0 0 [swapper/9] > 0 0 10 ffffa09e40f91f80 RU 0.0 0 0 [swapper/10] > 0 0 11 ffffa09e40f93f00 RU 0.0 0 0 [swapper/11] > 0 0 12 ffffa09e40f90000 RU 0.0 0 0 [swapper/12] > 0 0 13 ffffa09e40f9bf00 RU 0.0 0 0 [swapper/13] > 0 0 14 ffffa09e40f98000 RU 0.0 0 0 [swapper/14] > 0 0 15 ffffa09e40f9de80 RU 0.0 0 0 [swapper/15] It works well as expected. Reported-by: kernel test robot Suggested-by: Kees Cook Signed-off-by: Yafang Shao Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek --- fs/binfmt_elf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index a813b70f594e..138956fd4a88 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1572,7 +1572,7 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct 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(); - strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); + get_task_comm(psinfo->pr_fname, p); return 0; } From patchwork Mon Nov 1 06:04:14 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12595827 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F104BC4332F for ; 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Sun, 31 Oct 2021 23:04:43 -0700 (PDT) Received: from localhost.localdomain ([144.202.123.152]) by smtp.gmail.com with ESMTPSA id g8sm3277586pfc.65.2021.10.31.23.04.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Oct 2021 23:04:43 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Alexei Starovoitov , Andrii Nakryiko Subject: [PATCH v7 06/11] samples/bpf/test_overhead_kprobe_kern: make it adopt to task comm size change Date: Mon, 1 Nov 2021 06:04:14 +0000 Message-Id: <20211101060419.4682-7-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org bpf_probe_read_kernel_str() will add a nul terminator to the dst, then we don't care about if the dst size is big enough. This patch also replaces the hard-coded 16 with TASK_COMM_LEN to make it adopt to task comm size change. Signed-off-by: Yafang Shao Reviewed-by: Kees Cook Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek --- samples/bpf/offwaketime_kern.c | 4 ++-- samples/bpf/test_overhead_kprobe_kern.c | 11 ++++++----- samples/bpf/test_overhead_tp_kern.c | 5 +++-- 3 files changed, 11 insertions(+), 9 deletions(-) diff --git a/samples/bpf/offwaketime_kern.c b/samples/bpf/offwaketime_kern.c index 4866afd054da..eb4d94742e6b 100644 --- a/samples/bpf/offwaketime_kern.c +++ b/samples/bpf/offwaketime_kern.c @@ -113,11 +113,11 @@ static inline int update_counts(void *ctx, u32 pid, u64 delta) /* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ struct sched_switch_args { unsigned long long pad; - char prev_comm[16]; + char prev_comm[TASK_COMM_LEN]; int prev_pid; int prev_prio; long long prev_state; - char next_comm[16]; + char next_comm[TASK_COMM_LEN]; int next_pid; int next_prio; }; diff --git a/samples/bpf/test_overhead_kprobe_kern.c b/samples/bpf/test_overhead_kprobe_kern.c index f6d593e47037..8fdd2c9c56b2 100644 --- a/samples/bpf/test_overhead_kprobe_kern.c +++ b/samples/bpf/test_overhead_kprobe_kern.c @@ -6,6 +6,7 @@ */ #include #include +#include #include #include #include @@ -22,17 +23,17 @@ int prog(struct pt_regs *ctx) { struct signal_struct *signal; struct task_struct *tsk; - char oldcomm[16] = {}; - char newcomm[16] = {}; + char oldcomm[TASK_COMM_LEN] = {}; + char newcomm[TASK_COMM_LEN] = {}; u16 oom_score_adj; u32 pid; tsk = (void *)PT_REGS_PARM1(ctx); pid = _(tsk->pid); - bpf_probe_read_kernel(oldcomm, sizeof(oldcomm), &tsk->comm); - bpf_probe_read_kernel(newcomm, sizeof(newcomm), - (void *)PT_REGS_PARM2(ctx)); + bpf_probe_read_kernel_str(oldcomm, sizeof(oldcomm), &tsk->comm); + bpf_probe_read_kernel_str(newcomm, sizeof(newcomm), + (void *)PT_REGS_PARM2(ctx)); signal = _(tsk->signal); oom_score_adj = _(signal->oom_score_adj); return 0; diff --git a/samples/bpf/test_overhead_tp_kern.c b/samples/bpf/test_overhead_tp_kern.c index eaa32693f8fc..80edadacb692 100644 --- a/samples/bpf/test_overhead_tp_kern.c +++ b/samples/bpf/test_overhead_tp_kern.c @@ -4,6 +4,7 @@ * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. */ +#include #include #include @@ -11,8 +12,8 @@ struct task_rename { __u64 pad; __u32 pid; - char oldcomm[16]; - char newcomm[16]; + char oldcomm[TASK_COMM_LEN]; + char newcomm[TASK_COMM_LEN]; __u16 oom_score_adj; }; SEC("tracepoint/task/task_rename") From patchwork Mon Nov 1 06:04:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12595825 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1FF2C433EF for ; Mon, 1 Nov 2021 06:05:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE3E260EBC for ; Mon, 1 Nov 2021 06:05:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231698AbhKAGHz (ORCPT ); Mon, 1 Nov 2021 02:07:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231393AbhKAGHe (ORCPT ); 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Sun, 31 Oct 2021 23:04:45 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Alexei Starovoitov , Andrii Nakryiko Subject: [PATCH v7 07/11] tools/bpf/bpftool/skeleton: make it adopt to task comm size change Date: Mon, 1 Nov 2021 06:04:15 +0000 Message-Id: <20211101060419.4682-8-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org bpf_probe_read_kernel_str() will add a nul terminator to the dst, then we don't care about if the dst size is big enough. Signed-off-by: Yafang Shao Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek Acked-by: Andrii Nakryiko --- tools/bpf/bpftool/skeleton/pid_iter.bpf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/bpf/bpftool/skeleton/pid_iter.bpf.c b/tools/bpf/bpftool/skeleton/pid_iter.bpf.c index d9b420972934..f70702fcb224 100644 --- a/tools/bpf/bpftool/skeleton/pid_iter.bpf.c +++ b/tools/bpf/bpftool/skeleton/pid_iter.bpf.c @@ -71,8 +71,8 @@ int iter(struct bpf_iter__task_file *ctx) e.pid = task->tgid; e.id = get_obj_id(file->private_data, obj_type); - bpf_probe_read_kernel(&e.comm, sizeof(e.comm), - task->group_leader->comm); + bpf_probe_read_kernel_str(&e.comm, sizeof(e.comm), + task->group_leader->comm); bpf_seq_write(ctx->meta->seq, &e, sizeof(e)); return 0; From patchwork Mon Nov 1 06:04:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12595833 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07BC0C433FE for ; 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Sun, 31 Oct 2021 23:04:48 -0700 (PDT) Received: from localhost.localdomain ([144.202.123.152]) by smtp.gmail.com with ESMTPSA id g8sm3277586pfc.65.2021.10.31.23.04.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Oct 2021 23:04:47 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Alexei Starovoitov , Andrii Nakryiko Subject: [PATCH v7 08/11] tools/perf/test: make perf test adopt to task comm size change Date: Mon, 1 Nov 2021 06:04:16 +0000 Message-Id: <20211101060419.4682-9-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org kernel test robot reported a perf-test failure after I extended task comm size from 16 to 24. The failure as follows, 2021-10-13 18:00:46 sudo /usr/src/perf_selftests-x86_64-rhel-8.3-317419b91ef4eff4e2f046088201e4dc4065caa0/tools/perf/perf test 15 15: Parse sched tracepoints fields : FAILED! The reason is perf-test requires a fixed-size task comm. If we extend task comm size to 24, it will not equil with the required size 16 in perf test. After some analyzation, I found perf itself can adopt to the size change, for example, below is the output of perf-sched after I extend comm size to 24 - task 614 ( kthreadd: 84), nr_events: 1 task 615 ( systemd: 843), nr_events: 1 task 616 ( networkd-dispat: 1026), nr_events: 1 task 617 ( systemd: 846), nr_events: 1 $ cat /proc/843/comm networkd-dispatcher The task comm can be displayed correctly as expected. Replace old hard-coded 16 with the new one can fix the warning, but we'd better make the test accept both old and new sizes, then it can be backward compatibility. After this patch, the perf-test succeeds no matter task comm is 16 or 24 - 15: Parse sched tracepoints fields : Ok This patch is a preparation for the followup patch. Reported-by: kernel test robot Suggested-by: Arnaldo Carvalho de Melo Signed-off-by: Yafang Shao Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek --- tools/include/linux/sched.h | 11 +++++++++++ tools/perf/tests/evsel-tp-sched.c | 26 ++++++++++++++++++++------ 2 files changed, 31 insertions(+), 6 deletions(-) create mode 100644 tools/include/linux/sched.h diff --git a/tools/include/linux/sched.h b/tools/include/linux/sched.h new file mode 100644 index 000000000000..0d575afd7f43 --- /dev/null +++ b/tools/include/linux/sched.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TOOLS_LINUX_SCHED_H +#define _TOOLS_LINUX_SCHED_H + +/* Keep both length for backward compatibility */ +enum { + TASK_COMM_LEN_16 = 16, + TASK_COMM_LEN = 24, +}; + +#endif /* _TOOLS_LINUX_SCHED_H */ diff --git a/tools/perf/tests/evsel-tp-sched.c b/tools/perf/tests/evsel-tp-sched.c index f9e34bd26cf3..029f2a8c8e51 100644 --- a/tools/perf/tests/evsel-tp-sched.c +++ b/tools/perf/tests/evsel-tp-sched.c @@ -1,11 +1,13 @@ // SPDX-License-Identifier: GPL-2.0 #include +#include #include #include "evsel.h" #include "tests.h" #include "debug.h" -static int evsel__test_field(struct evsel *evsel, const char *name, int size, bool should_be_signed) +static int evsel__test_field_alt(struct evsel *evsel, const char *name, + int size, int alternate_size, bool should_be_signed) { struct tep_format_field *field = evsel__field(evsel, name); int is_signed; @@ -23,15 +25,24 @@ static int evsel__test_field(struct evsel *evsel, const char *name, int size, bo ret = -1; } - if (field->size != size) { - pr_debug("%s: \"%s\" size (%d) should be %d!\n", + if (field->size != size && field->size != alternate_size) { + pr_debug("%s: \"%s\" size (%d) should be %d", evsel->name, name, field->size, size); + if (alternate_size > 0) + pr_debug(" or %d", alternate_size); + pr_debug("!\n"); ret = -1; } return ret; } +static int evsel__test_field(struct evsel *evsel, const char *name, + int size, bool should_be_signed) +{ + return evsel__test_field_alt(evsel, name, size, -1, should_be_signed); +} + int test__perf_evsel__tp_sched_test(struct test *test __maybe_unused, int subtest __maybe_unused) { struct evsel *evsel = evsel__newtp("sched", "sched_switch"); @@ -42,7 +53,8 @@ int test__perf_evsel__tp_sched_test(struct test *test __maybe_unused, int subtes return -1; } - if (evsel__test_field(evsel, "prev_comm", 16, false)) + if (evsel__test_field_alt(evsel, "prev_comm", TASK_COMM_LEN_16, + TASK_COMM_LEN, false)) ret = -1; if (evsel__test_field(evsel, "prev_pid", 4, true)) @@ -54,7 +66,8 @@ int test__perf_evsel__tp_sched_test(struct test *test __maybe_unused, int subtes if (evsel__test_field(evsel, "prev_state", sizeof(long), true)) ret = -1; - if (evsel__test_field(evsel, "next_comm", 16, false)) + if (evsel__test_field_alt(evsel, "next_comm", TASK_COMM_LEN_16, + TASK_COMM_LEN, false)) ret = -1; if (evsel__test_field(evsel, "next_pid", 4, true)) @@ -72,7 +85,8 @@ int test__perf_evsel__tp_sched_test(struct test *test __maybe_unused, int subtes return -1; } - if (evsel__test_field(evsel, "comm", 16, false)) + if (evsel__test_field_alt(evsel, "comm", TASK_COMM_LEN_16, + TASK_COMM_LEN, false)) ret = -1; if (evsel__test_field(evsel, "pid", 4, true)) From patchwork Mon Nov 1 06:04:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12595829 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 526C5C433F5 for ; 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Sun, 31 Oct 2021 23:04:50 -0700 (PDT) Received: from localhost.localdomain ([144.202.123.152]) by smtp.gmail.com with ESMTPSA id g8sm3277586pfc.65.2021.10.31.23.04.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Oct 2021 23:04:49 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Andrii Nakryiko Subject: [PATCH v7 09/11] tools/testing/selftests/bpf: make it adopt to task comm size change Date: Mon, 1 Nov 2021 06:04:17 +0000 Message-Id: <20211101060419.4682-10-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The hard-coded 16 is used in various bpf progs. These progs get task comm either via bpf_get_current_comm() or prctl() or bpf_core_read_str(), all of which can work well even if the task comm size is changed. In these BPF programs, one thing to be improved is the sched:sched_switch tracepoint args. As the tracepoint args are derived from the kernel, we'd better make it same with the kernel. So the macro TASK_COMM_LEN is converted to type enum, then all the BPF programs can get it through BTF. The BPF program which wants to use TASK_COMM_LEN should include the header vmlinux.h. Regarding the test_stacktrace_map and test_tracepoint, as the type defined in linux/bpf.h are also defined in vmlinux.h, so we don't need to include linux/bpf.h again. Signed-off-by: Yafang Shao Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek Acked-by: Andrii Nakryiko --- include/linux/sched.h | 9 +++++++-- tools/testing/selftests/bpf/progs/test_stacktrace_map.c | 6 +++--- tools/testing/selftests/bpf/progs/test_tracepoint.c | 6 +++--- 3 files changed, 13 insertions(+), 8 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index b9c85c52fed0..09ac13e54549 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -274,8 +274,13 @@ struct task_group; #define get_current_state() READ_ONCE(current->__state) -/* Task command name length: */ -#define TASK_COMM_LEN 16 +/* + * Define the task command name length as enum, then it can be visible to + * BPF programs. + */ +enum { + TASK_COMM_LEN = 16, +}; extern void scheduler_tick(void); diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c index 00ed48672620..e9b602a6dc1b 100644 --- a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c +++ b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2018 Facebook -#include +#include #include #ifndef PERF_MAX_STACK_DEPTH @@ -41,11 +41,11 @@ struct { /* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ struct sched_switch_args { unsigned long long pad; - char prev_comm[16]; + char prev_comm[TASK_COMM_LEN]; int prev_pid; int prev_prio; long long prev_state; - char next_comm[16]; + char next_comm[TASK_COMM_LEN]; int next_pid; int next_prio; }; diff --git a/tools/testing/selftests/bpf/progs/test_tracepoint.c b/tools/testing/selftests/bpf/progs/test_tracepoint.c index 4b825ee122cf..f21982681e28 100644 --- a/tools/testing/selftests/bpf/progs/test_tracepoint.c +++ b/tools/testing/selftests/bpf/progs/test_tracepoint.c @@ -1,17 +1,17 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2017 Facebook -#include +#include #include /* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ struct sched_switch_args { unsigned long long pad; - char prev_comm[16]; + char prev_comm[TASK_COMM_LEN]; int prev_pid; int prev_prio; long long prev_state; - char next_comm[16]; + char next_comm[TASK_COMM_LEN]; int next_pid; int next_prio; }; From patchwork Mon Nov 1 06:04:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12595831 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C516C433F5 for ; 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Sun, 31 Oct 2021 23:04:52 -0700 (PDT) Received: from localhost.localdomain ([144.202.123.152]) by smtp.gmail.com with ESMTPSA id g8sm3277586pfc.65.2021.10.31.23.04.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Oct 2021 23:04:52 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Alexei Starovoitov , Andrii Nakryiko Subject: [PATCH v7 10/11] sched.h: extend task comm from 16 to 24 Date: Mon, 1 Nov 2021 06:04:18 +0000 Message-Id: <20211101060419.4682-11-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org When I was implementing a new per-cpu kthread cfs_migration, I found the comm of it "cfs_migration/%u" is truncated due to the limitation of TASK_COMM_LEN. For example, the comm of the percpu thread on CPU10~19 are all with the same name "cfs_migration/1", which will confuse the user. This issue is not critical, because we can get the corresponding CPU from the task's Cpus_allowed. But for kthreads correspoinding to other hardware devices, it is not easy to get the detailed device info from task comm, for example, jbd2/nvme0n1p2- xfs-reclaim/sdf We can also shorten the name to work around this problem, but I find there are so many truncated kthreads: rcu_tasks_kthre rcu_tasks_rude_ rcu_tasks_trace poll_mpt3sas0_s ext4-rsv-conver xfs-reclaim/sd{a, b, c, ...} xfs-blockgc/sd{a, b, c, ...} xfs-inodegc/sd{a, b, c, ...} audit_send_repl ecryptfs-kthrea vfio-irqfd-clea jbd2/nvme0n1p2- ... We should improve this problem fundamentally by extending comm size to 24 bytes. task_struct is growing rather regularly by 8 bytes. After this change, the truncated kthreads listed above will be displayed as: rcu_tasks_kthread rcu_tasks_rude_kthread rcu_tasks_trace_kthread poll_mpt3sas0_statu ext4-rsv-conversion xfs-reclaim/sdf1 xfs-blockgc/sdf1 xfs-inodegc/sdf1 audit_send_reply ecryptfs-kthread vfio-irqfd-cleanup jbd2/nvme0n1p2-8 As we have converted all the unsafe copy of task comm to the safe one, this change won't make any trouble to the kernel or the in-tree tools. The safe one and unsafe one of comm copy as follows, Unsafe Safe strlcpy strscpy_pad strncpy strscpy_pad bpf_probe_read_kernel bpf_probe_read_kernel_str bpf_core_read_str bpf_get_current_comm perf_event__prepare_comm prctl(2) Regarding the possible risk it may take to the out-of-tree user tools, if the user tools get the task comm through kernel API like prctl(2), bpf_get_current_comm() and etc, the tools still work well after this change. While If the user tools get the task comm through direct string copy, it must make sure the copied string should be with a nul terminator. Signed-off-by: Yafang Shao Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek --- include/linux/sched.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 09ac13e54549..a8822e26653e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -276,10 +276,11 @@ struct task_group; /* * Define the task command name length as enum, then it can be visible to - * BPF programs. + * BPF programs. The TASK_COMM_LEN_16 is kept for backward-compitability. */ enum { - TASK_COMM_LEN = 16, + TASK_COMM_LEN_16 = 16, + TASK_COMM_LEN = 24, }; extern void scheduler_tick(void); From patchwork Mon Nov 1 06:04:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 12595835 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3B98C433F5 for ; Mon, 1 Nov 2021 06:05:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC39161078 for ; Mon, 1 Nov 2021 06:05:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231963AbhKAGIW (ORCPT ); Mon, 1 Nov 2021 02:08:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231663AbhKAGHn (ORCPT ); Mon, 1 Nov 2021 02:07:43 -0400 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D3B8C06122C; Sun, 31 Oct 2021 23:04:55 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id l13so5851568pls.3; Sun, 31 Oct 2021 23:04:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=QKwddORb13OigBCy9mDZcUnsG5h+t9yQLv8LVp5siCU=; b=j5LFKzVUzTdpQtOquEYQiQ93/QxNXDe/080ZPzqen1nnJEcnWv0Arg1m3H5YGUWw8M stUDWkjS1zFBojQqjlqwmgBfiFDvw/FY5w1DdoEUTOEo04//87rHjl76eKfDkRV6JYaD wHniweh+Bt9WBNr9zbaJOafXiibJeSYbktM2cOjCLSm/QMXoinVi4CBxQO0XAGBypciT vft62rQAmLIxRWsns2FxpBvhq592YznXCJfnsuQVHL7l548rjILVi1WcAe1E24RkOJBv 6xba3tgT8iJOTopxgjfSx7YFqWx5gxJbgzz6VMxiVUScwsGxaEWyzxex2OUaialtPu/r 8Emw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=QKwddORb13OigBCy9mDZcUnsG5h+t9yQLv8LVp5siCU=; b=ejNQ3ZWHYJ19MF44lpdAswwzMjH2DL96bejXoDBGJAc0yB6p4zPTy9VxORoYptl/eq /9vgSu2bQPmJid/zehsBnikd2cp2bT23NCEQdWNwdRjjYOKp/Qinu5nlmoTIE8I+yv0e SqeZ34xks1kPdOcxHMPmSKeh1c0ccqEmY7MzcexY4yjw28vkYUcChIepqZ48NPmavZbj 3H2PAQbaeqACGG+kANVuRKRu/KQESYdVYfbI5dj1mPck5c/toMUY3itLBn9HQNPCkL91 U0guMUc42RUlVvy5PzTDkCaMz9mS8uB4dEiGatyk5IEkgBMnfKrN8QDCMuts4vW9LZ5o wLoQ== X-Gm-Message-State: AOAM532L6cDo/KB5/i9IBKqGbrfkTDURPrr5iLGtUPKy58Ek0xVOsbo6 0zbbSb4qccEH7vl3mgus5ck= X-Google-Smtp-Source: ABdhPJyrJq+mOKZ0lf2kZ6Y6bPXWfxcFbUFKsxFZDJ2CDMm20OFCcbYj+83X+q3vioiE0f2mNOqwFQ== X-Received: by 2002:a17:90a:930c:: with SMTP id p12mr36038293pjo.176.1635746695055; Sun, 31 Oct 2021 23:04:55 -0700 (PDT) Received: from localhost.localdomain ([144.202.123.152]) by smtp.gmail.com with ESMTPSA id g8sm3277586pfc.65.2021.10.31.23.04.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Oct 2021 23:04:54 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Alexei Starovoitov , Andrii Nakryiko Subject: [PATCH v7 11/11] kernel/kthread: show a warning if kthread's comm is truncated Date: Mon, 1 Nov 2021 06:04:19 +0000 Message-Id: <20211101060419.4682-12-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com> References: <20211101060419.4682-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Show a warning if task comm is truncated. Below is the result of my test case: truncated kthread comm:I-am-a-kthread-with-a-l (pid:178) by 8 characters As we have extended task comm to 24, all the existing in-tree kthreads/workqueues are not truncated anymore. So this warning will only be printed for the newly introduced one if it has a long name. Suggested-by: Petr Mladek Signed-off-by: Yafang Shao Reviewed-by: Kees Cook Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek --- kernel/kthread.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/kernel/kthread.c b/kernel/kthread.c index 5b37a8567168..63f38d3a4f62 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -399,12 +399,17 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), if (!IS_ERR(task)) { static const struct sched_param param = { .sched_priority = 0 }; char name[TASK_COMM_LEN]; + int len; /* * task is already visible to other tasks, so updating * COMM must be protected. */ - vsnprintf(name, sizeof(name), namefmt, args); + len = vsnprintf(name, sizeof(name), namefmt, args); + if (len >= TASK_COMM_LEN) { + pr_warn("truncated kthread comm:%s (pid:%d) by %d characters\n", + name, task->pid, len - TASK_COMM_LEN + 1); + } set_task_comm(task, name); /* * root may have changed our (kthreadd's) priority or CPU mask.