diff options
| author | Andi Kleen <[email protected]> | 2020-12-22 09:40:10 -0800 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2020-12-22 13:06:10 -0800 |
| commit | e14fd4ba8fb47fcf5f244366ec01ae94490cd86a (patch) | |
| tree | a80fd68c5097cb09c264c13515655362b40da9c5 | |
| parent | 8653b778e454a7708847aeafe689bce07aeeb94e (diff) | |
x86/split-lock: Avoid returning with interrupts enabled
When a split lock is detected always make sure to disable interrupts
before returning from the trap handler.
The kernel exit code assumes that all exits run with interrupts
disabled, otherwise the SWAPGS sequence can race against interrupts and
cause recursing page faults and later panics.
The problem will only happen on CPUs with split lock disable
functionality, so Icelake Server, Tiger Lake, Snow Ridge, Jacobsville.
Fixes: ca4c6a9858c2 ("x86/traps: Make interrupt enable/disable symmetric in C code")
Fixes: bce9b042ec73 ("x86/traps: Disable interrupts in exc_aligment_check()") # v5.8+
Signed-off-by: Andi Kleen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Tony Luck <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | arch/x86/kernel/traps.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index fb55981f2a0d..7f5aec758f0e 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -303,11 +303,12 @@ DEFINE_IDTENTRY_ERRORCODE(exc_alignment_check) local_irq_enable(); if (handle_user_split_lock(regs, error_code)) - return; + goto out; do_trap(X86_TRAP_AC, SIGBUS, "alignment check", regs, error_code, BUS_ADRALN, NULL); +out: local_irq_disable(); } |