6.7-stable review patch. If anyone has any objections, please let me know.
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From: Jiri Bohac jbohac@suse.cz
commit 7fd817c906503b6813ea3b41f5fdf4192449a707 upstream.
SETUP_RNG_SEED in setup_data is supplied by kexec and should not be reserved in the e820 map.
Doing so reserves 16 bytes of RAM when booting with kexec. (16 bytes because data->len is zeroed by parse_setup_data so only sizeof(setup_data) is reserved.)
When kexec is used repeatedly, each boot adds two entries in the kexec-provided e820 map as the 16-byte range splits a larger range of usable memory. Eventually all of the 128 available entries get used up. The next split will result in losing usable memory as the new entries cannot be added to the e820 map.
Fixes: 68b8e9713c8e ("x86/setup: Use rng seeds from setup_data") Signed-off-by: Jiri Bohac jbohac@suse.cz Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Cc: stable@kernel.org Link: https://lore.kernel.org/r/ZbmOjKnARGiaYBd5@dwarf.suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kernel/e820.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -1017,10 +1017,12 @@ void __init e820__reserve_setup_data(voi e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
/* - * SETUP_EFI and SETUP_IMA are supplied by kexec and do not need - * to be reserved. + * SETUP_EFI, SETUP_IMA and SETUP_RNG_SEED are supplied by + * kexec and do not need to be reserved. */ - if (data->type != SETUP_EFI && data->type != SETUP_IMA) + if (data->type != SETUP_EFI && + data->type != SETUP_IMA && + data->type != SETUP_RNG_SEED) e820__range_update_kexec(pa_data, sizeof(*data) + data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);