From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Shuah Khan <shuah@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Cc: mhiramat@kernel.org, linux-kernel@vger.kernel.org,
Andy Lutomirski <luto@amacapital.net>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Changbin Du <changbin.du@gmail.com>, Jann Horn <jannh@google.com>,
Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@kernel.org>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Nadav Amit <namit@vmware.com>,
Joel Fernandes <joel@joelfernandes.org>,
yhs@fb.com
Subject: [PATCH -tip v8 1/6] x86/uaccess: Allow access_ok() in irq context if pagefault_disabled
Date: Fri, 10 May 2019 00:13:12 +0900 [thread overview]
Message-ID: <155741479183.28419.514998815944825483.stgit@devnote2> (raw)
In-Reply-To: <155741476971.28419.15837024173365724167.stgit@devnote2>
WARN_ON_IN_IRQ() assumes that the access_ok() and following
user memory access can sleep. But this assumption is not
always correct; when the pagefault is disabled, following
memory access will just returns -EFAULT and never sleep.
Add pagefault_disabled() check in WARN_ON_ONCE() so that
it can ignore the case we call it with disabling pagefault.
For this purpose, this modified pagefault_disabled() as
an inline function.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
arch/x86/include/asm/uaccess.h | 4 +++-
include/linux/uaccess.h | 5 ++++-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index c82abd6e4ca3..9c4435307ff8 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -66,7 +66,9 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un
})
#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
-# define WARN_ON_IN_IRQ() WARN_ON_ONCE(!in_task())
+static inline bool pagefault_disabled(void);
+# define WARN_ON_IN_IRQ() \
+ WARN_ON_ONCE(!in_task() && !pagefault_disabled())
#else
# define WARN_ON_IN_IRQ()
#endif
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 2b70130af585..5a43ef7db492 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -203,7 +203,10 @@ static inline void pagefault_enable(void)
/*
* Is the pagefault handler disabled? If so, user access methods will not sleep.
*/
-#define pagefault_disabled() (current->pagefault_disabled != 0)
+static inline bool pagefault_disabled(void)
+{
+ return current->pagefault_disabled != 0;
+}
/*
* The pagefault handler is in general disabled by pagefault_disable() or
next prev parent reply other threads:[~2019-05-09 15:13 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-09 15:12 [PATCH -tip v8 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
2019-05-09 15:13 ` Masami Hiramatsu [this message]
2019-05-09 15:13 ` [PATCH -tip v8 2/6] uaccess: Add non-pagefault user-space read functions Masami Hiramatsu
2019-05-09 15:13 ` [PATCH -tip v8 3/6] tracing/probe: Add ustring type for user-space string Masami Hiramatsu
2019-05-14 7:24 ` Ingo Molnar
2019-05-14 10:10 ` Masami Hiramatsu
2019-05-09 15:13 ` [PATCH -tip v8 4/6] tracing/probe: Support user-space dereference Masami Hiramatsu
2019-05-09 15:13 ` [PATCH -tip v8 5/6] selftests/ftrace: Add user-memory access syntax testcase Masami Hiramatsu
2019-05-09 15:14 ` [PATCH -tip v8 6/6] perf-probe: Add user memory access attribute support Masami Hiramatsu
2019-05-13 18:38 ` [PATCH -tip v8 0/6] tracing/probes: uaccess: Add support user-space access Arnaldo Carvalho de Melo
2019-05-14 5:02 ` Masami Hiramatsu
2019-05-14 14:01 ` Arnaldo Carvalho de Melo
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