diff options
| author | Andy Lutomirski <luto@kernel.org> | 2020-02-25 22:36:38 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-02-27 14:48:39 +0100 |
| commit | 55ba18d6ed37a28cf8b8ca79e9aef4cf98183bb7 (patch) | |
| tree | f0d9a458cc23549c7bb8f152665132c892814fec /arch/x86/kernel/cpu | |
| parent | 3d51507f29f2153a658df4a0674ec5b592b62085 (diff) | |
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
Diffstat (limited to 'arch/x86/kernel/cpu')
| -rw-r--r-- | arch/x86/kernel/cpu/mce/core.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 2c4f949611e4..32ecc5969d59 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. |