From: David Engraf david.engraf@sysgo.com
commit 0a32c88ddb9af30e8a16d41d7b9b824c27d29459 upstream.
Commit 6d502b6ba1b2 ("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: David Engraf david.engraf@sysgo.com Reviwed-by: Mark Brown broonie@kernel.org Fixes: 6d502b6ba1b267b3 ("arm64: signal: nofpsimd: Handle fp/simd context for signal frames") Cc: stable@vger.kernel.org # 5.6.x Reviewed-by: Catalin Marinas catalin.marinas@arm.com Link: https://lore.kernel.org/r/20220225104008.820289-1-david.engraf@sysgo.com Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kernel/signal.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -577,10 +577,12 @@ static int setup_sigframe_layout(struct { int err;
- err = sigframe_alloc(user, &user->fpsimd_offset, - sizeof(struct fpsimd_context)); - if (err) - return 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) {