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Subject[PATCH] Revert "efi/random: Treat EFI_RNG_PROTOCOL output as bootloader randomness"
Date
This reverts commit 18b915ac6b0ac5ba7ded03156860f60a9f16df2b.

When CONFIG_RANDOM_TRUST_BOOTLOADER is enabled add_bootloader_randomness()
calls add_hwgenerator_randomness() which might sleep, but this is not
possible during early kernel initialization. This revert fixes following
NULL pointer deference:

[ 0.000000] efi: seeding entropy pool
[ 0.000000] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
...
[ 0.000000] pc : kthread_should_stop+0x2c/0x60
[ 0.000000] lr : add_hwgenerator_randomness+0x58/0x178
...
[ 0.000000] Call trace:
[ 0.000000] kthread_should_stop+0x2c/0x60
[ 0.000000] add_bootloader_randomness+0x2c/0x38
[ 0.000000] efi_config_parse_tables+0x120/0x250
[ 0.000000] efi_init+0x138/0x1e0
[ 0.000000] setup_arch+0x394/0x778
[ 0.000000] start_kernel+0x90/0x568

Signed-off-by: Ivan T. Ivanov <iivanov@suse.de>
---
drivers/firmware/efi/efi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 847f33ffc4ae..8aad3c524947 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -600,7 +600,7 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables,
sizeof(*seed) + size);
if (seed != NULL) {
pr_notice("seeding entropy pool\n");
- add_bootloader_randomness(seed->bits, size);
+ add_device_randomness(seed->bits, size);
early_memunmap(seed, sizeof(*seed) + size);
} else {
pr_err("Could not map UEFI random seed!\n");
--
2.33.0
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