diff options
| author | Linus Walleij <linus.walleij@linaro.org> | 2024-10-23 13:05:34 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-12-09 10:41:03 +0100 |
| commit | 0cfd6929fa780a3ec417858ab4fe2e8e46b16659 (patch) | |
| tree | 5a04c3f6ae5905d07c7671c6a43e74543c4a2c51 | |
| parent | c86d26b4b089ca294b3b7d915a7da61edb77935f (diff) | |
ARM: 9431/1: mm: Pair atomic_set_release() with _read_acquire()
commit 93ee385254d53849c01dd8ab9bc9d02790ee7f0e upstream.
The code for syncing vmalloc memory PGD pointers is using
atomic_read() in pair with atomic_set_release() but the
proper pairing is atomic_read_acquire() paired with
atomic_set_release().
This is done to clearly instruct the compiler to not
reorder the memcpy() or similar calls inside the section
so that we do not observe changes to init_mm. memcpy()
calls should be identified by the compiler as having
unpredictable side effects, but let's try to be on the
safe side.
Cc: stable@vger.kernel.org
Fixes: d31e23aff011 ("ARM: mm: make vmalloc_seq handling SMP safe")
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm/mm/ioremap.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c index ff555823cceb..89f1c97f3079 100644 --- a/arch/arm/mm/ioremap.c +++ b/arch/arm/mm/ioremap.c @@ -141,7 +141,7 @@ void __check_vmalloc_seq(struct mm_struct *mm) int seq; do { - seq = atomic_read(&init_mm.context.vmalloc_seq); + seq = atomic_read_acquire(&init_mm.context.vmalloc_seq); memcpy_pgd(mm, VMALLOC_START, VMALLOC_END); if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) { unsigned long start = |