Merge branch 'bpf-unlocking-fix'

Daniel Borkmann says:

====================
BPF fix with regards to unlocking

This set fixes the issue Eric was reporting recently [1].
First patch is a prerequisite discussed with Laura that is
needed for the later fix in the second one. I've tested this
extensively and it does not reproduce anymore on my side
after the fix. Thanks & sorry about that!

  [1] https://www.spinics.net/lists/netdev/msg421877.html
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

9 files changed, 22 insertions, 5 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index bd04eace455c..e8ada79ec71f 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -222,6 +222,10 @@ config GENERIC_SMP_IDLE_THREAD
 config GENERIC_IDLE_POLL_SETUP
        bool
 
+# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
+config ARCH_HAS_SET_MEMORY
+        bool
+
 # Select if arch init_task initializer is different to init/init_task.c
 config ARCH_INIT_TASK
        bool
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 186c4c214e0a..edae056b2af0 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -4,6 +4,7 @@ config ARM
         select ARCH_CLOCKSOURCE_DATA
         select ARCH_HAS_DEVMEM_IS_ALLOWED
         select ARCH_HAS_ELF_RANDOMIZE
+        select ARCH_HAS_SET_MEMORY
         select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
         select ARCH_HAVE_CUSTOM_GPIO_H
         select ARCH_HAS_GCOV_PROFILE_ALL
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 111742126897..1853405a897e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -12,6 +12,7 @@ config ARM64
         select ARCH_HAS_GCOV_PROFILE_ALL
         select ARCH_HAS_GIGANTIC_PAGE
         select ARCH_HAS_KCOV
+        select ARCH_HAS_SET_MEMORY
         select ARCH_HAS_SG_CHAIN
         select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
         select ARCH_USE_CMPXCHG_LOCKREF
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 05d12104d270..a785554916c0 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -898,7 +898,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 
         bpf_flush_icache(header, ctx.image + ctx.idx);
 
-        set_memory_ro((unsigned long)header, header->pages);
+        bpf_jit_binary_lock_ro(header);
         prog->bpf_func = (void *)ctx.image;
         prog->jited = 1;
 
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index c6722112527d..094deb1abbe7 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -72,6 +72,7 @@ config S390
         select ARCH_HAS_GCOV_PROFILE_ALL
         select ARCH_HAS_GIGANTIC_PAGE
         select ARCH_HAS_KCOV
+        select ARCH_HAS_SET_MEMORY
         select ARCH_HAS_SG_CHAIN
         select ARCH_HAS_UBSAN_SANITIZE_ALL
         select ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index f1d0e62ec1dd..b49c52a02087 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -1327,7 +1327,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
                         print_fn_code(jit.prg_buf, jit.size_prg);
         }
         if (jit.prg_buf) {
-                set_memory_ro((unsigned long)header, header->pages);
+                bpf_jit_binary_lock_ro(header);
                 fp->bpf_func = (void *) jit.prg_buf;
                 fp->jited = 1;
         }
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e487493bbd47..434dd2a1c5f2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -53,6 +53,7 @@ config X86
         select ARCH_HAS_KCOV                    if X86_64
         select ARCH_HAS_MMIO_FLUSH
         select ARCH_HAS_PMEM_API                if X86_64
+        select ARCH_HAS_SET_MEMORY
         select ARCH_HAS_SG_CHAIN
         select ARCH_HAS_UBSAN_SANITIZE_ALL
         select ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 18a62e208826..32322ce9b405 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1165,7 +1165,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 
         if (image) {
                 bpf_flush_icache(header, image + proglen);
-                set_memory_ro((unsigned long)header, header->pages);
+                bpf_jit_binary_lock_ro(header);
                 prog->bpf_func = (void *)image;
                 prog->jited = 1;
         } else {
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 0c1cc9143cb2..0c167fdee5f7 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -551,7 +551,7 @@ static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
 
 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
 
-#ifdef CONFIG_DEBUG_SET_MODULE_RONX
+#ifdef CONFIG_ARCH_HAS_SET_MEMORY
 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 {
         set_memory_ro((unsigned long)fp, fp->pages);
@@ -562,6 +562,11 @@ static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
         set_memory_rw((unsigned long)fp, fp->pages);
 }
 
+static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
+{
+        set_memory_ro((unsigned long)hdr, hdr->pages);
+}
+
 static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
 {
         set_memory_rw((unsigned long)hdr, hdr->pages);
@@ -575,10 +580,14 @@ static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 {
 }
 
+static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
+{
+}
+
 static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
 {
 }
-#endif /* CONFIG_DEBUG_SET_MODULE_RONX */
+#endif /* CONFIG_ARCH_HAS_SET_MEMORY */
 
 static inline struct bpf_binary_header *
 bpf_jit_binary_hdr(const struct bpf_prog *fp)