All of lore.kernel.org
 help / color / mirror / Atom feed
From: guoren@kernel.org
To: guoren@kernel.org, arnd@arndb.de, gregkh@linuxfoundation.org
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-csky@vger.kernel.org, linux-xtensa@linux-xtensa.org,
	linux-riscv@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Guo Ren <guoren@linux.alibaba.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	stable@vger.kernel.org
Subject: [PATCH V4 4/4] csky: patch_text: Fixup last cpu should be master
Date: Thu,  7 Apr 2022 15:33:23 +0800	[thread overview]
Message-ID: <20220407073323.743224-5-guoren@kernel.org> (raw)
In-Reply-To: <20220407073323.743224-1-guoren@kernel.org>

From: Guo Ren <guoren@linux.alibaba.com>

These patch_text implementations are using stop_machine_cpuslocked
infrastructure with atomic cpu_count. The original idea: When the
master CPU patch_text, the others should wait for it. But current
implementation is using the first CPU as master, which couldn't
guarantee the remaining CPUs are waiting. This patch changes the
last CPU as the master to solve the potential risk.

Fixes: 33e53ae1ce41 ("csky: Add kprobes supported")
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: <stable@vger.kernel.org>
---
 arch/csky/kernel/probes/kprobes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
index 42920f25e73c..34ba684d5962 100644
--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -30,7 +30,7 @@ static int __kprobes patch_text_cb(void *priv)
 	struct csky_insn_patch *param = priv;
 	unsigned int addr = (unsigned int)param->addr;
 
-	if (atomic_inc_return(&param->cpu_count) == 1) {
+	if (atomic_inc_return(&param->cpu_count) == num_online_cpus()) {
 		*(u16 *) addr = cpu_to_le16(param->opcode);
 		dcache_wb_range(addr, addr + 2);
 		atomic_inc(&param->cpu_count);
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: guoren@kernel.org
To: guoren@kernel.org, arnd@arndb.de, gregkh@linuxfoundation.org
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-csky@vger.kernel.org, linux-xtensa@linux-xtensa.org,
	linux-riscv@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Guo Ren <guoren@linux.alibaba.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	stable@vger.kernel.org
Subject: [PATCH V4 4/4] csky: patch_text: Fixup last cpu should be master
Date: Thu,  7 Apr 2022 15:33:23 +0800	[thread overview]
Message-ID: <20220407073323.743224-5-guoren@kernel.org> (raw)
In-Reply-To: <20220407073323.743224-1-guoren@kernel.org>

From: Guo Ren <guoren@linux.alibaba.com>

These patch_text implementations are using stop_machine_cpuslocked
infrastructure with atomic cpu_count. The original idea: When the
master CPU patch_text, the others should wait for it. But current
implementation is using the first CPU as master, which couldn't
guarantee the remaining CPUs are waiting. This patch changes the
last CPU as the master to solve the potential risk.

Fixes: 33e53ae1ce41 ("csky: Add kprobes supported")
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: <stable@vger.kernel.org>
---
 arch/csky/kernel/probes/kprobes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
index 42920f25e73c..34ba684d5962 100644
--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -30,7 +30,7 @@ static int __kprobes patch_text_cb(void *priv)
 	struct csky_insn_patch *param = priv;
 	unsigned int addr = (unsigned int)param->addr;
 
-	if (atomic_inc_return(&param->cpu_count) == 1) {
+	if (atomic_inc_return(&param->cpu_count) == num_online_cpus()) {
 		*(u16 *) addr = cpu_to_le16(param->opcode);
 		dcache_wb_range(addr, addr + 2);
 		atomic_inc(&param->cpu_count);
-- 
2.25.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: guoren@kernel.org
To: guoren@kernel.org, arnd@arndb.de, gregkh@linuxfoundation.org
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-csky@vger.kernel.org, linux-xtensa@linux-xtensa.org,
	linux-riscv@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Guo Ren <guoren@linux.alibaba.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	stable@vger.kernel.org
Subject: [PATCH V4 4/4] csky: patch_text: Fixup last cpu should be master
Date: Thu,  7 Apr 2022 15:33:23 +0800	[thread overview]
Message-ID: <20220407073323.743224-5-guoren@kernel.org> (raw)
In-Reply-To: <20220407073323.743224-1-guoren@kernel.org>

From: Guo Ren <guoren@linux.alibaba.com>

These patch_text implementations are using stop_machine_cpuslocked
infrastructure with atomic cpu_count. The original idea: When the
master CPU patch_text, the others should wait for it. But current
implementation is using the first CPU as master, which couldn't
guarantee the remaining CPUs are waiting. This patch changes the
last CPU as the master to solve the potential risk.

Fixes: 33e53ae1ce41 ("csky: Add kprobes supported")
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: <stable@vger.kernel.org>
---
 arch/csky/kernel/probes/kprobes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
index 42920f25e73c..34ba684d5962 100644
--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -30,7 +30,7 @@ static int __kprobes patch_text_cb(void *priv)
 	struct csky_insn_patch *param = priv;
 	unsigned int addr = (unsigned int)param->addr;
 
-	if (atomic_inc_return(&param->cpu_count) == 1) {
+	if (atomic_inc_return(&param->cpu_count) == num_online_cpus()) {
 		*(u16 *) addr = cpu_to_le16(param->opcode);
 		dcache_wb_range(addr, addr + 2);
 		atomic_inc(&param->cpu_count);
-- 
2.25.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2022-04-07  7:35 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-07  7:33 [PATCH V4 0/4] arch: patch_text: Fixup last cpu should be master guoren
2022-04-07  7:33 ` guoren
2022-04-07  7:33 ` guoren
2022-04-07  7:33 ` [PATCH V4 1/4] arm64: " guoren
2022-04-07  7:33   ` guoren
2022-04-07  7:33   ` guoren
2022-04-07  7:33 ` [PATCH V4 2/4] riscv: " guoren
2022-04-07  7:33   ` guoren
2022-04-07  7:33   ` guoren
2022-04-07  7:33 ` [PATCH V4 3/4] xtensa: " guoren
2022-04-07  7:33   ` guoren
2022-04-07  7:33   ` guoren
2022-04-07  7:33 ` guoren [this message]
2022-04-07  7:33   ` [PATCH V4 4/4] csky: " guoren
2022-04-07  7:33   ` guoren
2022-04-08 13:58 ` [PATCH V4 0/4] arch: " Will Deacon
2022-04-08 13:58   ` Will Deacon
2022-04-08 13:58   ` Will Deacon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220407073323.743224-5-guoren@kernel.org \
    --to=guoren@kernel.org \
    --cc=arnd@arndb.de \
    --cc=gregkh@linuxfoundation.org \
    --cc=guoren@linux.alibaba.com \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-csky@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=linux-xtensa@linux-xtensa.org \
    --cc=mhiramat@kernel.org \
    --cc=stable@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.