Messages in this thread Patch in this message | | | Date | Sun, 22 Apr 2018 20:06:39 +0100 | From | Mark Rutland <> | Subject | Re: BUG: KASAN: global-out-of-bounds in unmap_kernel_at_el0+0x70/0x1a0 |
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On Sun, Apr 22, 2018 at 12:47:57PM +0200, Jan Kiszka wrote: > Hi, > > this can be triggered simply by running > > # echo 0 > /sys/devices/system/cpu/cpu3/online > # echo 1 > /sys/devices/system/cpu/cpu3/online > > [ 455.904854] ================================================================== > [ 455.906108] BUG: KASAN: global-out-of-bounds in unmap_kernel_at_el0+0x70/0x1a0 > [ 455.906668] Read of size 4 at addr ffff200008e3a9d8 by task swapper/3/0
It looks like we miss a sentinel in kpti_safe_list.
Does the below help?
Mark.
---->8---- From ade322407e3d6d1f50e558ebd50d2c1c7bd811c2 Mon Sep 17 00:00:00 2001 From: Mark Rutland <mark.rutland@arm.com> Date: Sun, 22 Apr 2018 19:58:08 +0100 Subject: [PATCH] arm64: add sentinel to kpti_safe_list
We're missing a sentinel entry in kpti_safe_list. Thus is_midr_in_range_list() can walk past the end of kpti_safe_list. Depending on the contents of memory, this could erroneously match a CPU's MIDR, cause a data abort, or other bad outcomes.
Add the sentinel entry to avoid this.
Fixes: be5b299830c63ed7 ("arm64: capabilities: Add support for checks based on a list of MIDRs") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reported-by: Jan Kiszka <jan.kiszka@web.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Will Deacon <will.deacon@arm.com> --- arch/arm64/kernel/cpufeature.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 536d572e5596..9d1b06d67c53 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -868,6 +868,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, static const struct midr_range kpti_safe_list[] = { MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2), MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN), + { /* sentinel */ } }; char const *str = "command line option"; -- 2.11.0
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