linux-kernel - [v2][PATCH 4/6] book3e/kgdb: Fix a single stgep case of lazy IRQ

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Mon, 21 Jan 2013 15:44:13 +0800
From:	Tiejun Chen <tiejun.chen@...driver.com>
To:	<benh@...nel.crashing.org>, <galak@...nel.crashing.org>
CC:	<linuxppc-dev@...ts.ozlabs.org>, <linux-kernel@...r.kernel.org>,
	<jason.wessel@...driver.com>
Subject: [v2][PATCH 4/6] book3e/kgdb: Fix a single stgep case of lazy IRQ

When we're in kgdb_singlestep(), we have to work around to get
thread_info by copying from the kernel stack before calling
kgdb_handle_exception(), then copying it back afterwards.

But for PPC64, we have a lazy interrupt implementation. So after
copying thread info frome kernle stack, if we need to replay an
interrupt, we shouldn't restore that previous backup thread info
to make sure we can replay an interrupt lately with a proper
thread info.

This patch use __check_irq_replay() to guarantee this process.

Signed-off-by: Tiejun Chen <tiejun.chen@...driver.com>
---
 arch/powerpc/kernel/irq.c  |   10 ++++++++++
 arch/powerpc/kernel/kgdb.c |    3 ++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 4f97fe3..bb8d27a 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -339,7 +339,17 @@ bool prep_irq_for_idle(void)
 	return true;
 }
 
+notrace unsigned int check_irq_replay(void)
+{
+	return __check_irq_replay();
+}
+#else
+notrace unsigned int check_irq_replay(void)
+{
+	return 0;
+}
 #endif /* CONFIG_PPC64 */
+EXPORT_SYMBOL(check_irq_replay);
 
 int arch_show_interrupts(struct seq_file *p, int prec)
 {
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index eb30a40..2f22807 100644
--- a/arch/powerpc/kernel/kgdb.c
+++ b/arch/powerpc/kernel/kgdb.c
@@ -151,6 +151,7 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs)
 	return 1;
 }
 
+extern notrace unsigned int check_irq_replay(void);
 static int kgdb_singlestep(struct pt_regs *regs)
 {
 	struct thread_info *thread_info, *exception_thread_info;
@@ -181,7 +182,7 @@ static int kgdb_singlestep(struct pt_regs *regs)
 
 	kgdb_handle_exception(0, SIGTRAP, 0, regs);
 
-	if (thread_info != exception_thread_info)
+	if ((thread_info != exception_thread_info) && (!check_irq_replay()))
 		/* Restore current_thread_info lastly. */
 		memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info);
 
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/