Re: [PATCH v5 1/6] kexec: move locking into do_kexec_load
Arnd Bergmann writes:
> From: Arnd Bergmann
>
> The locking is the same between the native and compat version of
> sys_kexec_load(), so it can be done in the common implementation
> to reduce duplication.
Acked-by: "Eric W. Biederman"
>
> Co-developed-by: Eric Biederman
> Co-developed-by: Christoph Hellwig
> Signed-off-by: Arnd Bergmann
> ---
> kernel/kexec.c | 44
> 1 file changed, 16 insertions(+), 28 deletions(-)
>
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index c82c6c06f051..9c7aef8f4bb6 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -110,6 +110,17 @@ static int do_kexec_load(unsigned long entry, unsigned
> long nr_segments,
> unsigned long i;
> int ret;
>
> + /*
> + * Because we write directly to the reserved memory region when loading
> + * crash kernels we need a mutex here to prevent multiple crash kernels
> + * from attempting to load simultaneously, and to prevent a crash kernel
> + * from loading over the top of a in use crash kernel.
> + *
> + * KISS: always take the mutex.
> + */
> + if (!mutex_trylock(_mutex))
> + return -EBUSY;
> +
> if (flags & KEXEC_ON_CRASH) {
> dest_image = _crash_image;
> if (kexec_crash_image)
> @@ -121,7 +132,8 @@ static int do_kexec_load(unsigned long entry, unsigned
> long nr_segments,
> if (nr_segments == 0) {
> /* Uninstall image */
> kimage_free(xchg(dest_image, NULL));
> - return 0;
> + ret = 0;
> + goto out_unlock;
> }
> if (flags & KEXEC_ON_CRASH) {
> /*
> @@ -134,7 +146,7 @@ static int do_kexec_load(unsigned long entry, unsigned
> long nr_segments,
>
> ret = kimage_alloc_init(, entry, nr_segments, segments, flags);
> if (ret)
> - return ret;
> + goto out_unlock;
>
> if (flags & KEXEC_PRESERVE_CONTEXT)
> image->preserve_context = 1;
> @@ -171,6 +183,8 @@ static int do_kexec_load(unsigned long entry, unsigned
> long nr_segments,
> arch_kexec_protect_crashkres();
>
> kimage_free(image);
> +out_unlock:
> + mutex_unlock(_mutex);
> return ret;
> }
>
> @@ -247,21 +261,8 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry,
> unsigned long, nr_segments,
> ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
> return -EINVAL;
>
> - /* Because we write directly to the reserved memory
> - * region when loading crash kernels we need a mutex here to
> - * prevent multiple crash kernels from attempting to load
> - * simultaneously, and to prevent a crash kernel from loading
> - * over the top of a in use crash kernel.
> - *
> - * KISS: always take the mutex.
> - */
> - if (!mutex_trylock(_mutex))
> - return -EBUSY;
> -
> result = do_kexec_load(entry, nr_segments, segments, flags);
>
> - mutex_unlock(_mutex);
> -
> return result;
> }
>
> @@ -301,21 +302,8 @@ COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry,
> return -EFAULT;
> }
>
> - /* Because we write directly to the reserved memory
> - * region when loading crash kernels we need a mutex here to
> - * prevent multiple crash kernels from attempting to load
> - * simultaneously, and to prevent a crash kernel from loading
> - * over the top of a in use crash kernel.
> - *
> - * KISS: always take the mutex.
> - */
> - if (!mutex_trylock(_mutex))
> - return -EBUSY;
> -
> result = do_kexec_load(entry, nr_segments, ksegments, flags);
>
> - mutex_unlock(_mutex);
> -
> return result;
> }
> #endif
[PATCH v5 1/6] kexec: move locking into do_kexec_load
From: Arnd Bergmann
The locking is the same between the native and compat version of
sys_kexec_load(), so it can be done in the common implementation
to reduce duplication.
Co-developed-by: Eric Biederman
Co-developed-by: Christoph Hellwig
Signed-off-by: Arnd Bergmann
---
kernel/kexec.c | 44
1 file changed, 16 insertions(+), 28 deletions(-)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index c82c6c06f051..9c7aef8f4bb6 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -110,6 +110,17 @@ static int do_kexec_load(unsigned long entry, unsigned
long nr_segments,
unsigned long i;
int ret;
+ /*
+* Because we write directly to the reserved memory region when loading
+* crash kernels we need a mutex here to prevent multiple crash kernels
+* from attempting to load simultaneously, and to prevent a crash kernel
+* from loading over the top of a in use crash kernel.
+*
+* KISS: always take the mutex.
+*/
+ if (!mutex_trylock(_mutex))
+ return -EBUSY;
+
if (flags & KEXEC_ON_CRASH) {
dest_image = _crash_image;
if (kexec_crash_image)
@@ -121,7 +132,8 @@ static int do_kexec_load(unsigned long entry, unsigned long
nr_segments,
if (nr_segments == 0) {
/* Uninstall image */
kimage_free(xchg(dest_image, NULL));
- return 0;
+ ret = 0;
+ goto out_unlock;
}
if (flags & KEXEC_ON_CRASH) {
/*
@@ -134,7 +146,7 @@ static int do_kexec_load(unsigned long entry, unsigned long
nr_segments,
ret = kimage_alloc_init(, entry, nr_segments, segments, flags);
if (ret)
- return ret;
+ goto out_unlock;
if (flags & KEXEC_PRESERVE_CONTEXT)
image->preserve_context = 1;
@@ -171,6 +183,8 @@ static int do_kexec_load(unsigned long entry, unsigned long
nr_segments,
arch_kexec_protect_crashkres();
kimage_free(image);
+out_unlock:
+ mutex_unlock(_mutex);
return ret;
}
@@ -247,21 +261,8 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned
long, nr_segments,
((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
return -EINVAL;
- /* Because we write directly to the reserved memory
-* region when loading crash kernels we need a mutex here to
-* prevent multiple crash kernels from attempting to load
-* simultaneously, and to prevent a crash kernel from loading
-* over the top of a in use crash kernel.
-*
-* KISS: always take the mutex.
-*/
- if (!mutex_trylock(_mutex))
- return -EBUSY;
-
result = do_kexec_load(entry, nr_segments, segments, flags);
- mutex_unlock(_mutex);
-
return result;
}
@@ -301,21 +302,8 @@ COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry,
return -EFAULT;
}
- /* Because we write directly to the reserved memory
-* region when loading crash kernels we need a mutex here to
-* prevent multiple crash kernels from attempting to load
-* simultaneously, and to prevent a crash kernel from loading
-* over the top of a in use crash kernel.
-*
-* KISS: always take the mutex.
-*/
- if (!mutex_trylock(_mutex))
- return -EBUSY;
-
result = do_kexec_load(entry, nr_segments, ksegments, flags);
- mutex_unlock(_mutex);
-
return result;
}
#endif
--
2.29.2
