From: Arnd Bergmann <arnd(a)arndb.de>
commit 4b692e861619353ce069e547a67c8d0e32d9ef3d upstream.
Patch series "compat: remove compat_alloc_user_space", v5.
Going through compat_alloc_user_space() to convert indirect system call
arguments tends to add complexity compared to handling the native and
compat logic in the same code.
This patch (of 6):
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.
Link: https://lkml.kernel.org/r/20210727144859.4150043-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20210727144859.4150043-2-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd(a)arndb.de>
Co-developed-by: Eric Biederman <ebiederm(a)xmission.com>
Co-developed-by: Christoph Hellwig <hch(a)infradead.org>
Acked-by: "Eric W. Biederman" <ebiederm(a)xmission.com>
Cc: Catalin Marinas <catalin.marinas(a)arm.com>
Cc: Will Deacon <will(a)kernel.org>
Cc: Thomas Bogendoerfer <tsbogend(a)alpha.franken.de>
Cc: "James E.J. Bottomley" <James.Bottomley(a)HansenPartnership.com>
Cc: Helge Deller <deller(a)gmx.de>
Cc: Michael Ellerman <mpe(a)ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh(a)kernel.crashing.org>
Cc: Paul Mackerras <paulus(a)samba.org>
Cc: Heiko Carstens <hca(a)linux.ibm.com>
Cc: Vasily Gorbik <gor(a)linux.ibm.com>
Cc: Christian Borntraeger <borntraeger(a)de.ibm.com>
Cc: "David S. Miller" <davem(a)davemloft.net>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: "H. Peter Anvin" <hpa(a)zytor.com>
Cc: Al Viro <viro(a)zeniv.linux.org.uk>
Cc: Feng Tang <feng.tang(a)intel.com>
Cc: Christoph Hellwig <hch(a)lst.de>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: stable(a)vger.kernel.org # 5.10+
Signed-off-by: Wen Yang <wenyang.linux(a)foxmail.com>
---
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(&kexec_mutex))
+ return -EBUSY;
+
if (flags & KEXEC_ON_CRASH) {
dest_image = &kexec_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(&image, 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(&kexec_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(&kexec_mutex))
- return -EBUSY;
-
result = do_kexec_load(entry, nr_segments, segments, flags);
- mutex_unlock(&kexec_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(&kexec_mutex))
- return -EBUSY;
-
result = do_kexec_load(entry, nr_segments, ksegments, flags);
- mutex_unlock(&kexec_mutex);
-
return result;
}
#endif
--
2.37.2