linux-kernel - [PATCH V5 1/3] x86/efi: Make efi_delete_dummy_variable() use set_variable_nonblocking() instead of set

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Message-Id: <1527560464-19466-2-git-send-email-sai.praneeth.prakhya@intel.com>
Date:   Mon, 28 May 2018 19:21:02 -0700
From:   Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>
To:     linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Sai Praneeth <sai.praneeth.prakhya@...el.com>,
        Lee Chun-Yi <jlee@...e.com>, Borislav Petkov <bp@...en8.de>,
        Tony Luck <tony.luck@...el.com>,
        Will Deacon <will.deacon@....com>,
        Dave Hansen <dave.hansen@...el.com>,
        Mark Rutland <mark.rutland@....com>,
        Bhupesh Sharma <bhsharma@...hat.com>,
        Naresh Bhat <naresh.bhat@...aro.org>,
        Ricardo Neri <ricardo.neri@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ravi Shankar <ravi.v.shankar@...el.com>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        Dan Williams <dan.j.williams@...el.com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
Subject: [PATCH V5 1/3] x86/efi: Make efi_delete_dummy_variable() use set_variable_nonblocking() instead of set_variable()

From: Sai Praneeth <sai.praneeth.prakhya@...el.com>

Presently, efi_delete_dummy_variable() uses set_variable() which might
block and hence kernel prints stack trace with a warning "bad:
scheduling from the idle thread!". So, make efi_delete_dummy_variable()
use set_variable_nonblocking(), which, as the name suggests doesn't
block.

Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>
Suggested-by: Andy Lutomirski <luto@...nel.org>
Cc: Lee Chun-Yi <jlee@...e.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Tony Luck <tony.luck@...el.com>
Cc: Will Deacon <will.deacon@....com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Bhupesh Sharma <bhsharma@...hat.com>
Cc: Naresh Bhat <naresh.bhat@...aro.org>
Cc: Ricardo Neri <ricardo.neri@...el.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ravi Shankar <ravi.v.shankar@...el.com>
Cc: Matt Fleming <matt@...eblueprint.co.uk>
Cc: Dan Williams <dan.j.williams@...el.com>
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
---
 arch/x86/platform/efi/quirks.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 36c1f8b9f7e0..6af39dc40325 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -105,12 +105,11 @@ early_param("efi_no_storage_paranoia", setup_storage_paranoia);
 */
 void efi_delete_dummy_variable(void)
 {
-	efi.set_variable((efi_char16_t *)efi_dummy_name,
-			 &EFI_DUMMY_GUID,
-			 EFI_VARIABLE_NON_VOLATILE |
-			 EFI_VARIABLE_BOOTSERVICE_ACCESS |
-			 EFI_VARIABLE_RUNTIME_ACCESS,
-			 0, NULL);
+	efi.set_variable_nonblocking((efi_char16_t *)efi_dummy_name,
+				     &EFI_DUMMY_GUID,
+				     EFI_VARIABLE_NON_VOLATILE |
+				     EFI_VARIABLE_BOOTSERVICE_ACCESS |
+				     EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL);
 }
 
 /*
-- 
2.7.4