linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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 v9 1/6] x86/uaccess: Allow access_ok() in irq context if pagefault_disabled
Date: Wed, 15 May 2019 14:38:06 +0900	[thread overview]
Message-ID: <155789868664.26965.7932665824135793317.stgit@devnote2> (raw)
In-Reply-To: <155789866428.26965.8344923934342528416.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


  reply	other threads:[~2019-05-15  5:38 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-15  5:37 [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
2019-05-15  5:38 ` Masami Hiramatsu [this message]
2019-05-15  5:38 ` [PATCH -tip v9 2/6] uaccess: Add non-pagefault user-space read functions Masami Hiramatsu
2019-05-15  5:38 ` [PATCH -tip v9 3/6] tracing/probe: Add ustring type for user-space string Masami Hiramatsu
2019-05-15  5:38 ` [PATCH -tip v9 4/6] tracing/probe: Support user-space dereference Masami Hiramatsu
2019-05-15  5:38 ` [PATCH -tip v9 5/6] selftests/ftrace: Add user-memory access syntax testcase Masami Hiramatsu
2019-05-15  5:39 ` [PATCH -tip v9 6/6] perf-probe: Add user memory access attribute support Masami Hiramatsu
2019-05-15  5:55 ` [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Ingo Molnar
2019-05-15  8:49   ` Masami Hiramatsu
2019-05-20 15:26   ` Steven Rostedt
2019-05-21  8:28     ` Ingo Molnar
2019-05-21 12:57       ` Steven Rostedt
2019-05-21 15:57         ` Masami Hiramatsu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=155789868664.26965.7932665824135793317.stgit@devnote2 \
    --to=mhiramat@kernel.org \
    --cc=acme@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=alexei.starovoitov@gmail.com \
    --cc=changbin.du@gmail.com \
    --cc=jannh@google.com \
    --cc=joel@joelfernandes.org \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@amacapital.net \
    --cc=luto@kernel.org \
    --cc=mingo@kernel.org \
    --cc=namit@vmware.com \
    --cc=peterz@infradead.org \
    --cc=rostedt@goodmis.org \
    --cc=shuah@kernel.org \
    --cc=torvalds@linux-foundation.org \
    --cc=yhs@fb.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).