Commit 0a32c88d authored by David Engraf's avatar David Engraf Committed by Will Deacon
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arm64: signal: nofpsimd: Do not allocate fp/simd context when not available 



Commit 6d502b6b ("arm64: signal: nofpsimd: Handle fp/simd context for
signal frames") introduced saving the fp/simd context for signal handling
only when support is available. But setup_sigframe_layout() always
reserves memory for fp/simd context. The additional memory is not touched
because preserve_fpsimd_context() is not called and thus the magic is
invalid.

This may lead to an error when parse_user_sigframe() checks the fp/simd
area and does not find a valid magic number.

Signed-off-by: default avatarDavid Engraf <david.engraf@sysgo.com>
Reviwed-by: default avatarMark Brown <broonie@kernel.org>
Fixes: 6d502b6b ("arm64: signal: nofpsimd: Handle fp/simd context for signal frames")
Cc: <stable@vger.kernel.org> # 5.6.x
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220225104008.820289-1-david.engraf@sysgo.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 0a2eec83

arch/arm64/kernel/signal.c

+6 −4
Original line number Diff line number Diff line
@@ -577,10 +577,12 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, 
{

	int err;



	if (system_supports_fpsimd()) {

		err = sigframe_alloc(user, &user->fpsimd_offset,

				     sizeof(struct fpsimd_context));

		if (err)

			return err;

	}



	/* fault information, if valid */

	if (add_all || current->thread.fault_code) {