linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: tip-bot for Thomas Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: luto@kernel.org, linux-kernel@vger.kernel.org,
	vincenzo.frascino@arm.com, tglx@linutronix.de, mingo@kernel.org,
	hpa@zytor.com
Subject: [tip:timers/urgent] lib/vdso/32: Remove inconsistent NULL pointer checks
Date: Tue, 30 Jul 2019 15:19:09 -0700	[thread overview]
Message-ID: <tip-a9446a906f52292c52ecbd5be78eaa4d8395756c@git.kernel.org> (raw)
In-Reply-To: <20190728131648.587523358@linutronix.de>

Commit-ID:  a9446a906f52292c52ecbd5be78eaa4d8395756c
Gitweb:     https://git.kernel.org/tip/a9446a906f52292c52ecbd5be78eaa4d8395756c
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Sun, 28 Jul 2019 15:12:52 +0200
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 31 Jul 2019 00:09:09 +0200

lib/vdso/32: Remove inconsistent NULL pointer checks

The 32bit variants of vdso_clock_gettime()/getres() have a NULL pointer
check for the timespec pointer. That's inconsistent vs. 64bit.

But the vdso implementation will never be consistent versus the syscall
because the only case which it can handle is NULL. Any other invalid
pointer will cause a segfault. So special casing NULL is not really useful.

Remove it along with the superflouos syscall fallback invocation as that
will return -EFAULT anyway. That also gets rid of the dubious typecast
which only works because the pointer is NULL.

Fixes: 00b26474c2f1 ("lib/vdso: Provide generic VDSO implementation")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20190728131648.587523358@linutronix.de

---
 lib/vdso/gettimeofday.c | 18 ++----------------
 1 file changed, 2 insertions(+), 16 deletions(-)

diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index 2d1c1f241fd9..e28f5a607a5f 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -115,9 +115,6 @@ __cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
 	struct __kernel_timespec ts;
 	int ret;
 
-	if (res == NULL)
-		goto fallback;
-
 	ret = __cvdso_clock_gettime(clock, &ts);
 
 	if (ret == 0) {
@@ -126,9 +123,6 @@ __cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
 	}
 
 	return ret;
-
-fallback:
-	return clock_gettime_fallback(clock, (struct __kernel_timespec *)res);
 }
 
 static __maybe_unused int
@@ -204,10 +198,8 @@ int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
 		goto fallback;
 	}
 
-	if (res) {
-		res->tv_sec = 0;
-		res->tv_nsec = ns;
-	}
+	res->tv_sec = 0;
+	res->tv_nsec = ns;
 
 	return 0;
 
@@ -221,9 +213,6 @@ __cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
 	struct __kernel_timespec ts;
 	int ret;
 
-	if (res == NULL)
-		goto fallback;
-
 	ret = __cvdso_clock_getres(clock, &ts);
 
 	if (ret == 0) {
@@ -232,8 +221,5 @@ __cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
 	}
 
 	return ret;
-
-fallback:
-	return clock_getres_fallback(clock, (struct __kernel_timespec *)res);
 }
 #endif /* VDSO_HAS_CLOCK_GETRES */

  parent reply	other threads:[~2019-07-30 22:19 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-28 13:12 [patch 0/5] lib/vdso, x86/vdso: Fix fallout from generic VDSO conversion Thomas Gleixner
2019-07-28 13:12 ` [patch 1/5] lib/vdso/32: Remove inconsistent NULL pointer checks Thomas Gleixner
2019-07-28 14:33   ` Andy Lutomirski
2019-07-28 14:42     ` Thomas Gleixner
2019-07-28 15:30   ` Vincenzo Frascino
2019-07-29 14:52   ` Sean Christopherson
2019-07-30 22:19   ` tip-bot for Thomas Gleixner [this message]
2019-07-28 13:12 ` [patch 2/5] lib/vdso: Move fallback invocation to the callers Thomas Gleixner
2019-07-28 14:37   ` Andy Lutomirski
2019-07-28 15:31   ` Vincenzo Frascino
2019-07-30 22:19   ` [tip:timers/urgent] " tip-bot for Thomas Gleixner
2019-07-28 13:12 ` [patch 3/5] lib/vdso/32: Provide legacy syscall fallbacks Thomas Gleixner
2019-07-28 14:39   ` Andy Lutomirski
2019-07-28 15:33   ` Vincenzo Frascino
2019-07-29 14:48   ` Sean Christopherson
2019-07-30  9:38     ` [patch V2 " Thomas Gleixner
2019-07-30 14:28       ` Sean Christopherson
2019-07-30 20:09       ` Andy Lutomirski
2019-07-30 20:14         ` Thomas Gleixner
2019-07-30 22:20       ` [tip:timers/urgent] " tip-bot for Thomas Gleixner
2019-07-28 13:12 ` [patch 4/5] x86/vdso/32: Use 32bit syscall fallback Thomas Gleixner
2019-07-28 14:50   ` Andy Lutomirski
2019-07-29 11:23   ` Vincenzo Frascino
2019-07-29 14:51   ` Sean Christopherson
2019-07-30 22:21   ` [tip:timers/urgent] " tip-bot for Thomas Gleixner
2019-07-28 13:12 ` [patch 5/5] arm64: compat: vdso: Use legacy syscalls as fallback Thomas Gleixner
2019-07-28 15:35   ` Vincenzo Frascino
2019-07-30 22:22   ` [tip:timers/urgent] " tip-bot for Thomas Gleixner

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=tip-a9446a906f52292c52ecbd5be78eaa4d8395756c@git.kernel.org \
    --to=tipbot@zytor.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tip-commits@vger.kernel.org \
    --cc=luto@kernel.org \
    --cc=mingo@kernel.org \
    --cc=tglx@linutronix.de \
    --cc=vincenzo.frascino@arm.com \
    --subject='Re: [tip:timers/urgent] lib/vdso/32: Remove inconsistent NULL pointer checks' \
    /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

This is a public inbox, see mirroring instructions
on how to clone and mirror all data and code used for this inbox