linux-kernel - [PATCH 4.14 18/48] lib/crc32test: remove extra local_irq

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Date:   Mon,  9 Nov 2020 13:55:27 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Vasily Gorbik <gor@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 4.14 18/48] lib/crc32test: remove extra local_irq_disable/enable

From: Vasily Gorbik <gor@...ux.ibm.com>

commit aa4e460f0976351fddd2f5ac6e08b74320c277a1 upstream.

Commit 4d004099a668 ("lockdep: Fix lockdep recursion") uncovered the
following issue in lib/crc32test reported on s390:

  BUG: using __this_cpu_read() in preemptible [00000000] code: swapper/0/1
  caller is lockdep_hardirqs_on_prepare+0x48/0x270
  CPU: 6 PID: 1 Comm: swapper/0 Not tainted 5.9.0-next-20201015-15164-g03d992bd2de6 #19
  Hardware name: IBM 3906 M04 704 (LPAR)
  Call Trace:
    lockdep_hardirqs_on_prepare+0x48/0x270
    trace_hardirqs_on+0x9c/0x1b8
    crc32_test.isra.0+0x170/0x1c0
    crc32test_init+0x1c/0x40
    do_one_initcall+0x40/0x130
    do_initcalls+0x126/0x150
    kernel_init_freeable+0x1f6/0x230
    kernel_init+0x22/0x150
    ret_from_fork+0x24/0x2c
  no locks held by swapper/0/1.

Remove extra local_irq_disable/local_irq_enable helpers calls.

Fixes: 5fb7f87408f1 ("lib: add module support to crc32 tests")
Signed-off-by: Vasily Gorbik <gor@...ux.ibm.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Link: https://lkml.kernel.org/r/patch.git-4369da00c06e.your-ad-here.call-01602859837-ext-1679@work.hours
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 lib/crc32test.c |    4 ----
 1 file changed, 4 deletions(-)

--- a/lib/crc32test.c
+++ b/lib/crc32test.c
@@ -683,7 +683,6 @@ static int __init crc32c_test(void)
 
 	/* reduce OS noise */
 	local_irq_save(flags);
-	local_irq_disable();
 
 	nsec = ktime_get_ns();
 	for (i = 0; i < 100; i++) {
@@ -694,7 +693,6 @@ static int __init crc32c_test(void)
 	nsec = ktime_get_ns() - nsec;
 
 	local_irq_restore(flags);
-	local_irq_enable();
 
 	pr_info("crc32c: CRC_LE_BITS = %d\n", CRC_LE_BITS);
 
@@ -768,7 +766,6 @@ static int __init crc32_test(void)
 
 	/* reduce OS noise */
 	local_irq_save(flags);
-	local_irq_disable();
 
 	nsec = ktime_get_ns();
 	for (i = 0; i < 100; i++) {
@@ -783,7 +780,6 @@ static int __init crc32_test(void)
 	nsec = ktime_get_ns() - nsec;
 
 	local_irq_restore(flags);
-	local_irq_enable();
 
 	pr_info("crc32: CRC_LE_BITS = %d, CRC_BE BITS = %d\n",
 		 CRC_LE_BITS, CRC_BE_BITS);