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From: "tip-bot2 for Petr Mladek" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Petr Mladek <pmladek@suse.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Alexandre Chartre <alexandre.chartre@oracle.com>,
	x86 <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: [tip: core/rcu] printk: Prepare for nested printk_nmi_enter()
Date: Tue, 19 May 2020 19:52:37 -0000	[thread overview]
Message-ID: <158991795708.17951.10946630610236060760.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20200505134100.681374113@linutronix.de>

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     8c4e93c362ff114def211d4629b120af86eb1275
Gitweb:        https://git.kernel.org/tip/8c4e93c362ff114def211d4629b120af86eb1275
Author:        Petr Mladek <pmladek@suse.com>
AuthorDate:    Mon, 24 Feb 2020 13:13:31 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Tue, 19 May 2020 15:51:16 +02:00

printk: Prepare for nested printk_nmi_enter()

There is plenty of space in the printk_context variable. Reserve one byte
there for the NMI context to be on the safe side.

It should never overflow. The BUG_ON(in_nmi() == NMI_MASK) in nmi_enter()
will trigger much earlier.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134100.681374113@linutronix.de



---
 kernel/printk/internal.h    | 8 +++++---
 kernel/printk/printk_safe.c | 4 ++--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index b2b0f52..660f9a6 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -6,9 +6,11 @@
 
 #ifdef CONFIG_PRINTK
 
-#define PRINTK_SAFE_CONTEXT_MASK	 0x3fffffff
-#define PRINTK_NMI_DIRECT_CONTEXT_MASK	 0x40000000
-#define PRINTK_NMI_CONTEXT_MASK		 0x80000000
+#define PRINTK_SAFE_CONTEXT_MASK	0x007ffffff
+#define PRINTK_NMI_DIRECT_CONTEXT_MASK	0x008000000
+#define PRINTK_NMI_CONTEXT_MASK		0xff0000000
+
+#define PRINTK_NMI_CONTEXT_OFFSET	0x010000000
 
 extern raw_spinlock_t logbuf_lock;
 
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index d9a659a..e8791f2 100644
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -295,12 +295,12 @@ static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args)
 
 void notrace printk_nmi_enter(void)
 {
-	this_cpu_or(printk_context, PRINTK_NMI_CONTEXT_MASK);
+	this_cpu_add(printk_context, PRINTK_NMI_CONTEXT_OFFSET);
 }
 
 void notrace printk_nmi_exit(void)
 {
-	this_cpu_and(printk_context, ~PRINTK_NMI_CONTEXT_MASK);
+	this_cpu_sub(printk_context, PRINTK_NMI_CONTEXT_OFFSET);
 }
 
 /*

  reply	other threads:[~2020-05-19 19:52 UTC|newest]

Thread overview: 178+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-05 13:16 [patch V4 part 1 00/36] x86/entry: Entry/exception code rework, preparatory patches Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 01/36] rcu: Add comments marking transitions between RCU watching and not Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 02/36] x86/hw_breakpoint: Prevent data breakpoints on cpu_entry_area Thomas Gleixner
2020-05-06  8:14   ` Borislav Petkov
2020-05-06 12:11   ` Alexandre Chartre
2020-05-09  9:00   ` Lai Jiangshan
2020-05-09  9:23   ` Lai Jiangshan
2020-05-09 19:08     ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Andy Lutomirski
2020-05-05 13:16 ` [patch V4 part 1 03/36] sched: Clean up scheduler_ipi() Thomas Gleixner
2020-05-06  8:32   ` Thomas Gleixner
2020-05-06  8:40   ` Borislav Petkov
2020-05-06  9:12     ` Thomas Gleixner
2020-05-06 10:02       ` Borislav Petkov
2020-05-06 12:37   ` Alexandre Chartre
2020-05-06 15:03     ` Thomas Gleixner
2020-05-06 15:33     ` Peter Zijlstra
2020-05-06 18:28       ` Paul E. McKenney
2020-05-06 18:37         ` Peter Zijlstra
2020-05-06 18:46           ` Paul E. McKenney
2020-05-12 15:13   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra (Intel)
2020-05-05 13:16 ` [patch V4 part 1 04/36] sched: Make scheduler_ipi inline Thomas Gleixner
2020-05-06 12:42   ` Alexandre Chartre
2020-05-12 15:13   ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 05/36] x86/entry: Flip _TIF_SIGPENDING and _TIF_NOTIFY_RESUME handling Thomas Gleixner
2020-05-06 11:53   ` Miroslav Benes
2020-05-06 12:06     ` Thomas Gleixner
2020-05-06 15:35     ` Peter Zijlstra
2020-05-06 13:06   ` Alexandre Chartre
2020-05-06 16:26   ` Borislav Petkov
2020-05-07 17:35   ` Andy Lutomirski
2020-05-13 20:56   ` Mathieu Desnoyers
2020-05-13 21:10     ` Steven Rostedt
2020-05-13 22:48       ` Mathieu Desnoyers
2020-05-14  0:12       ` Thomas Gleixner
2020-05-14  0:37         ` Steven Rostedt
2020-05-14  0:49           ` Thomas Gleixner
2020-05-14  1:22         ` Andy Lutomirski
2020-05-14  2:51         ` Mathieu Desnoyers
2020-05-14  9:19           ` Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 06/36] compiler: Simple READ/WRITE_ONCE() implementations Thomas Gleixner
2020-05-06 13:11   ` Alexandre Chartre
2020-05-06 13:33   ` Will Deacon
2020-05-06 15:36     ` Peter Zijlstra
2020-05-06 16:33   ` Borislav Petkov
2020-05-05 13:16 ` [patch V4 part 1 07/36] locking/atomics: Flip fallbacks and instrumentation Thomas Gleixner
2020-05-05 16:04   ` Mark Rutland
2020-05-07 23:41   ` Steven Rostedt
2020-05-08  8:40     ` Peter Zijlstra
2020-05-12 14:36   ` [tip: locking/kcsan] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 08/36] x86/doublefault: Remove memmove() call Thomas Gleixner
2020-05-06 13:47   ` Alexandre Chartre
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 09/36] x86/entry/64: Avoid pointless code when CONTEXT_TRACKING=n Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 10/36] x86/entry: Remove the unused LOCKDEP_SYSEXIT cruft Thomas Gleixner
2020-05-06 13:52   ` Alexandre Chartre
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 11/36] x86/kvm: Handle async page faults directly through do_page_fault() Thomas Gleixner
2020-05-06  7:00   ` Paolo Bonzini
2020-05-06 14:05   ` Alexandre Chartre
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Andy Lutomirski
2020-05-05 13:16 ` [patch V4 part 1 12/36] x86/kvm: Sanitize kvm_async_pf_task_wait() Thomas Gleixner
2020-05-05 17:54   ` Paul E. McKenney
2020-05-05 21:50     ` Thomas Gleixner
2020-05-06  7:00   ` Paolo Bonzini
2020-05-06 12:53     ` Steven Rostedt
2020-05-06 15:13   ` Alexandre Chartre
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 13/36] x86/kvm: Restrict ASYNC_PF to user space Thomas Gleixner
2020-05-06  7:00   ` Paolo Bonzini
2020-05-06 15:29   ` Alexandre Chartre
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 14/36] x86/entry: Get rid of ist_begin/end_non_atomic() Thomas Gleixner
2020-05-06 15:34   ` Alexandre Chartre
2020-05-07 17:46   ` Andy Lutomirski
2020-05-13 22:57   ` Mathieu Desnoyers
2020-05-14  0:13     ` Steven Rostedt
2020-05-15  9:34     ` Thomas Gleixner
2020-05-15 13:11       ` Mathieu Desnoyers
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 15/36] kprobes: Lock kprobe_mutex while showing kprobe_blacklist Thomas Gleixner
2020-05-06 15:38   ` Alexandre Chartre
2020-05-12 15:18   ` [tip: core/kprobes] " tip-bot2 for Masami Hiramatsu
2020-05-05 13:16 ` [patch V4 part 1 16/36] kprobes: Support __kprobes blacklist in modules Thomas Gleixner
2020-05-06 15:47   ` Alexandre Chartre
2020-05-12 15:18   ` [tip: core/kprobes] " tip-bot2 for Masami Hiramatsu
2020-05-05 13:16 ` [patch V4 part 1 17/36] kprobes: Support NOKPROBE_SYMBOL() " Thomas Gleixner
2020-05-06 15:54   ` Alexandre Chartre
2020-05-12 15:18   ` [tip: core/kprobes] " tip-bot2 for Masami Hiramatsu
2020-05-05 13:16 ` [patch V4 part 1 18/36] samples/kprobes: Add __kprobes and NOKPROBE_SYMBOL() for handlers Thomas Gleixner
2020-05-06 15:57   ` Alexandre Chartre
2020-05-12 15:18   ` [tip: core/kprobes] " tip-bot2 for Masami Hiramatsu
2020-05-05 13:16 ` [patch V4 part 1 19/36] x86/entry: Exclude low level entry code from sanitizing Thomas Gleixner
2020-05-05 20:39   ` Brian Gerst
2020-05-06 15:42     ` Peter Zijlstra
2020-05-06 16:03   ` Alexandre Chartre
2020-05-13 22:58     ` Mathieu Desnoyers
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 20/36] vmlinux.lds.h: Create section for protection against instrumentation Thomas Gleixner
2020-05-06 16:08   ` Sean Christopherson
2020-05-06 16:28     ` Peter Zijlstra
2020-05-06 16:57       ` Thomas Gleixner
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 21/36] kprobes: Prevent probes in .noinstr.text section Thomas Gleixner
2020-05-08  6:30   ` Masami Hiramatsu
2020-05-19 19:52   ` [tip: core/kprobes] " tip-bot2 for Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 22/36] tracing: Provide lockdep less trace_hardirqs_on/off() variants Thomas Gleixner
2020-05-07 17:55   ` Andy Lutomirski
2020-05-07 18:52     ` Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 23/36] bug: Annotate WARN/BUG/stackfail as noinstr safe Thomas Gleixner
2020-05-13 23:12   ` Mathieu Desnoyers
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:16 ` [patch V4 part 1 24/36] lockdep: Prepare for noinstr sections Thomas Gleixner
2020-05-08  0:23   ` Steven Rostedt
2020-05-08  8:44     ` Peter Zijlstra
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 25/36] rcu/tree: Mark the idle relevant functions noinstr Thomas Gleixner
2020-05-05 18:07   ` Paul E. McKenney
2020-05-19 19:48   ` Joel Fernandes
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Thomas Gleixner
2020-09-28 22:22     ` Kim Phillips
2020-09-28 22:55       ` Paul E. McKenney
2020-09-29  7:25       ` Peter Zijlstra
2020-09-29 11:25     ` Peter Zijlstra
2020-09-29 14:34       ` Steven Rostedt
2020-09-29 14:52         ` Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 26/36] printk: Prepare for nested printk_nmi_enter() Thomas Gleixner
2020-05-19 19:52   ` tip-bot2 for Petr Mladek [this message]
2020-05-05 13:16 ` [patch V4 part 1 27/36] arm64: Prepare arch_nmi_enter() for recursion Thomas Gleixner
2020-05-13 23:28   ` Mathieu Desnoyers
2020-05-15 14:04     ` Frederic Weisbecker
2020-05-15 15:45       ` Will Deacon
2020-05-15 16:01         ` Mathieu Desnoyers
2020-05-15 21:29   ` Thomas Gleixner
2020-05-15 21:31     ` Frederic Weisbecker
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Frederic Weisbecker
2020-05-05 13:16 ` [patch V4 part 1 28/36] hardirq/nmi: Allow nested nmi_enter() Thomas Gleixner
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 29/36] x86/mce: Send #MC singal from task work Thomas Gleixner
2020-05-07 18:02   ` Andy Lutomirski
2020-05-08  8:48     ` Peter Zijlstra
2020-05-08 21:30       ` Andy Lutomirski
2020-05-14 14:16     ` Borislav Petkov
2020-05-13 23:42   ` Mathieu Desnoyers
2020-05-14 17:38     ` Thomas Gleixner
2020-05-14 17:42       ` Mathieu Desnoyers
2020-05-14 14:17   ` Borislav Petkov
2020-05-14 16:03     ` Mathieu Desnoyers
2020-05-14 16:19       ` Andy Lutomirski
2020-05-14 16:39       ` Borislav Petkov
2020-05-14 17:05         ` Mathieu Desnoyers
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 30/36] lockdep: Always inline lockdep_{off,on}() Thomas Gleixner
2020-05-13 23:46   ` Mathieu Desnoyers
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 31/36] printk: Disallow instrumenting print_nmi_enter() Thomas Gleixner
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 32/36] sh/ftrace: Move arch_ftrace_nmi_{enter,exit} into nmi exception Thomas Gleixner
2020-05-08  0:34   ` Steven Rostedt
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 33/36] x86,tracing: Robustify ftrace_nmi_enter() Thomas Gleixner
2020-05-08  6:19   ` Masami Hiramatsu
2020-05-05 13:16 ` [patch V4 part 1 34/36] sched,rcu,tracing: Avoid tracing before in_nmi() is correct Thomas Gleixner
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 35/36] x86: Replace ist_enter() with nmi_enter() Thomas Gleixner
2020-05-07 18:04   ` Andy Lutomirski
2020-05-07 18:17     ` Mathieu Desnoyers
2020-05-08  8:50       ` Peter Zijlstra
2020-05-08 17:12         ` Josh Poimboeuf
2020-05-14  0:12   ` Mathieu Desnoyers
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Peter Zijlstra
2020-05-05 13:16 ` [patch V4 part 1 36/36] rcu: Make RCU IRQ enter/exit functions rely on in_nmi() Thomas Gleixner
2020-05-05 18:13   ` Paul E. McKenney
2020-05-06 17:09   ` Alexandre Chartre
2020-05-19 19:52   ` [tip: core/rcu] " tip-bot2 for Paul E. McKenney
2020-05-07 18:05 ` [patch V4 part 1 00/36] x86/entry: Entry/exception code rework, preparatory patches Andy Lutomirski

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