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From: "tip-bot2 for Andy Lutomirski" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@suse.de>,
	Alexandre Chartre <alexandre.chartre@oracle.com>,
	x86 <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: [tip: x86/entry] x86/mce: Disable tracing and kprobes on do_machine_check()
Date: Thu, 27 Feb 2020 14:15:58 -0000	[thread overview]
Message-ID: <158281295888.28353.15787585336529193970.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20200225220216.315548935@linutronix.de>

The following commit has been merged into the x86/entry branch of tip:

Commit-ID:     55ba18d6ed37a28cf8b8ca79e9aef4cf98183bb7
Gitweb:        https://git.kernel.org/tip/55ba18d6ed37a28cf8b8ca79e9aef4cf98183bb7
Author:        Andy Lutomirski <luto@kernel.org>
AuthorDate:    Tue, 25 Feb 2020 22:36:38 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 27 Feb 2020 14:48:39 +01:00

x86/mce: Disable tracing and kprobes on do_machine_check()

do_machine_check() can be raised in almost any context including the most
fragile ones. Prevent kprobes and tracing.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200225220216.315548935@linutronix.de

---
 arch/x86/include/asm/traps.h   |  3 ---
 arch/x86/kernel/cpu/mce/core.c | 12 ++++++++++--
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index ffa0dc8..e1c660b 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -88,9 +88,6 @@ dotraplinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code,
 dotraplinkage void do_spurious_interrupt_bug(struct pt_regs *regs, long error_code);
 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code);
 dotraplinkage void do_alignment_check(struct pt_regs *regs, long error_code);
-#ifdef CONFIG_X86_MCE
-dotraplinkage void do_machine_check(struct pt_regs *regs, long error_code);
-#endif
 dotraplinkage void do_simd_coprocessor_error(struct pt_regs *regs, long error_code);
 #ifdef CONFIG_X86_32
 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code);
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 2c4f949..32ecc59 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1213,8 +1213,14 @@ static void __mc_scan_banks(struct mce *m, struct mce *final,
  * On Intel systems this is entered on all CPUs in parallel through
  * MCE broadcast. However some CPUs might be broken beyond repair,
  * so be always careful when synchronizing with others.
+ *
+ * Tracing and kprobes are disabled: if we interrupted a kernel context
+ * with IF=1, we need to minimize stack usage.  There are also recursion
+ * issues: if the machine check was due to a failure of the memory
+ * backing the user stack, tracing that reads the user stack will cause
+ * potentially infinite recursion.
  */
-void do_machine_check(struct pt_regs *regs, long error_code)
+void notrace do_machine_check(struct pt_regs *regs, long error_code)
 {
 	DECLARE_BITMAP(valid_banks, MAX_NR_BANKS);
 	DECLARE_BITMAP(toclear, MAX_NR_BANKS);
@@ -1360,6 +1366,7 @@ out_ist:
 	ist_exit(regs);
 }
 EXPORT_SYMBOL_GPL(do_machine_check);
+NOKPROBE_SYMBOL(do_machine_check);
 
 #ifndef CONFIG_MEMORY_FAILURE
 int memory_failure(unsigned long pfn, int flags)
@@ -1892,10 +1899,11 @@ static void unexpected_machine_check(struct pt_regs *regs, long error_code)
 void (*machine_check_vector)(struct pt_regs *, long error_code) =
 						unexpected_machine_check;
 
-dotraplinkage void do_mce(struct pt_regs *regs, long error_code)
+dotraplinkage notrace void do_mce(struct pt_regs *regs, long error_code)
 {
 	machine_check_vector(regs, error_code);
 }
+NOKPROBE_SYMBOL(do_mce);
 
 /*
  * Called for each booted CPU to set up machine checks.

  parent reply	other threads:[~2020-02-27 14:22 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-25 21:36 [patch 00/10] x86/entry: Consolidation - Part I Thomas Gleixner
2020-02-25 21:36 ` [patch 01/10] x86/entry/32: Add missing ASM_CLAC to general_protection entry Thomas Gleixner
2020-02-26  1:00   ` Frederic Weisbecker
2020-02-27 14:15   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-02-25 21:36 ` [patch 02/10] x86/mce: Disable tracing and kprobes on do_machine_check() Thomas Gleixner
2020-02-26  1:13   ` Frederic Weisbecker
2020-02-26  5:29     ` Andy Lutomirski
2020-02-26 13:28       ` Peter Zijlstra
2020-02-26 15:10         ` Andy Lutomirski
2020-02-26 16:08           ` Peter Zijlstra
2020-02-26 17:28             ` Andy Lutomirski
2020-02-26 18:42               ` Borislav Petkov
2020-02-26 18:59                 ` Peter Zijlstra
2020-02-26 19:09                   ` Andy Lutomirski
2020-02-26 20:59                     ` Steven Rostedt
2020-02-26 11:18   ` Borislav Petkov
2020-02-27 14:15   ` tip-bot2 for Andy Lutomirski [this message]
2020-02-25 21:36 ` [patch 03/10] x86/entry/32: Force MCE through do_mce() Thomas Gleixner
2020-02-26  1:11   ` Frederic Weisbecker
2020-02-27 14:15   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-02-25 21:36 ` [patch 04/10] x86/traps: Remove pointless irq enable from do_spurious_interrupt_bug() Thomas Gleixner
2020-02-26  1:19   ` Frederic Weisbecker
2020-02-25 21:36 ` [patch 05/10] x86/traps: Document do_spurious_interrupt_bug() Thomas Gleixner
2020-02-26 17:08   ` Frederic Weisbecker
2020-02-27 14:15   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-02-25 21:36 ` [patch 06/10] x86/traps: Remove redundant declaration of do_double_fault() Thomas Gleixner
2020-02-27 14:15   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-02-25 21:36 ` [patch 07/10] x86/irq: Remove useless return value from do_IRQ() Thomas Gleixner
2020-02-27 14:15   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-02-25 21:36 ` [patch 08/10] x86/entry/32: Remove the 0/-1 distinction from exception entries Thomas Gleixner
2020-02-26  5:34   ` Andy Lutomirski
2020-02-26 18:42     ` Thomas Gleixner
2020-02-26 18:57       ` Andy Lutomirski
2020-02-26 19:15         ` Thomas Gleixner
2020-02-27 14:24           ` [patch V2 " Thomas Gleixner
2020-02-29 11:49             ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-02-25 21:36 ` [patch 09/10] x86/entry/entry_32: Route int3 through common_exception Thomas Gleixner
2020-02-26 17:35   ` Frederic Weisbecker
2020-02-27 14:15   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-02-25 21:36 ` [patch 10/10] x86/traps: Stop using ist_enter/exit() in do_int3() Thomas Gleixner
2020-02-27 14:15   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-02-27 14:33   ` tip-bot2 for Andy Lutomirski
2020-02-26  5:26 ` [patch 00/10] x86/entry: Consolidation - Part I Andy Lutomirski
2020-02-26  5:35 ` Andy Lutomirski
2020-02-27 11:01 ` Alexandre Chartre

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