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由 Ard Biesheuvel 提交于
stable inclusion from stable-v5.10.164 commit 38c4a17c6b32f7c6679b30de390c466c7367fe6b category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I7T7G4 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=38c4a17c6b32f7c6679b30de390c466c7367fe6b -------------------------------- commit d3f45053 upstream. Nathan reports that recent kernels built with LTO will crash when doing EFI boot using Fedora's GRUB and SHIM. The culprit turns out to be a misaligned load from the TPM event log, which is annotated with READ_ONCE(), and under LTO, this gets translated into a LDAR instruction which does not tolerate misaligned accesses. Interestingly, this does not happen when booting the same kernel straight from the UEFI shell, and so the fact that the event log may appear misaligned in memory may be caused by a bug in GRUB or SHIM. However, using READ_ONCE() to access firmware tables is slightly unusual in any case, and here, we only need to ensure that 'event' is not dereferenced again after it gets unmapped, but this is already taken care of by the implicit barrier() semantics of the early_memunmap() call. Cc: <stable@vger.kernel.org> Cc: Peter Jones <pjones@redhat.com> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Reported-by: NNathan Chancellor <nathan@kernel.org> Tested-by: NNathan Chancellor <nathan@kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/1782Signed-off-by: NArd Biesheuvel <ardb@kernel.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Nsanglipeng <sanglipeng1@jd.com>
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