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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
	kernel test robot <lkp@intel.com>,
	Sasha Levin <sashal@kernel.org>,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	dave.hansen@linux.intel.com, x86@kernel.org,
	keescook@chromium.org, hpa@zytor.com
Subject: [PATCH AUTOSEL 5.4 28/34] x86/cpu: Elide KCSAN for cpu_has() and friends
Date: Tue,  7 Jun 2022 14:00:03 -0400	[thread overview]
Message-ID: <20220607180011.481266-28-sashal@kernel.org> (raw)
In-Reply-To: <20220607180011.481266-1-sashal@kernel.org>

From: Peter Zijlstra <peterz@infradead.org>

[ Upstream commit a6a5eb269f6f3a2fe392f725a8d9052190c731e2 ]

As x86 uses the <asm-generic/bitops/instrumented-*.h> headers, the
regular forms of all bitops are instrumented with explicit calls to
KASAN and KCSAN checks. As these are explicit calls, these are not
suppressed by the noinstr function attribute.

This can result in calls to those check functions in noinstr code, which
objtool warns about:

vmlinux.o: warning: objtool: enter_from_user_mode+0x24: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x28: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x24: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x24: call to __kcsan_check_access() leaves .noinstr.text section

Prevent this by using the arch_*() bitops, which are the underlying
bitops without explciit instrumentation.

[null: Changelog]
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220502111216.290518605@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/include/asm/cpufeature.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 59bf91c57aa8..619c1f80a2ab 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -49,7 +49,7 @@ extern const char * const x86_power_flags[32];
 extern const char * const x86_bug_flags[NBUGINTS*32];
 
 #define test_cpu_cap(c, bit)						\
-	 test_bit(bit, (unsigned long *)((c)->x86_capability))
+	 arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
 
 /*
  * There are 32 bits/features in each mask word.  The high bits
-- 
2.35.1


  parent reply	other threads:[~2022-06-07 18:49 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-07 17:59 [PATCH AUTOSEL 5.4 01/34] iio: dummy: iio_simple_dummy: check the return value of kstrdup() Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 02/34] iio: st_sensors: Add a local lock for protecting odr Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 03/34] lkdtm/usercopy: Expand size of "out of frame" object Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 04/34] tty: synclink_gt: Fix null-pointer-dereference in slgt_clean() Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 05/34] tty: Fix a possible resource leak in icom_probe Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 06/34] drivers: staging: rtl8192u: Fix deadlock in ieee80211_beacons_stop() Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 07/34] drivers: staging: rtl8192e: Fix deadlock in rtllib_beacons_stop() Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 08/34] USB: host: isp116x: check return value after calling platform_get_resource() Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 09/34] drivers: tty: serial: Fix deadlock in sa1100_set_termios() Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 10/34] drivers: usb: host: Fix deadlock in oxu_bus_suspend() Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 11/34] USB: hcd-pci: Fully suspend across freeze/thaw cycle Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 12/34] usb: dwc2: gadget: don't reset gadget's driver->bus Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 13/34] misc: rtsx: set NULL intfdata when probe fails Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 14/34] extcon: Modify extcon device to be created after driver data is set Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 15/34] clocksource/drivers/sp804: Avoid error on multiple instances Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 16/34] staging: rtl8712: fix uninit-value in usb_read8() and friends Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 17/34] staging: rtl8712: fix uninit-value in r871xu_drv_init() Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 18/34] serial: msm_serial: disable interrupts in __msm_console_write() Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 19/34] kernfs: Separate kernfs_pr_cont_buf and rename_lock Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 20/34] watchdog: wdat_wdt: Stop watchdog when rebooting the system Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 21/34] md: don't unregister sync_thread with reconfig_mutex held Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 22/34] md: protect md_unregister_thread from reentrancy Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 23/34] scsi: myrb: Fix up null pointer access on myrb_cleanup() Sasha Levin
2022-06-07 17:59 ` [PATCH AUTOSEL 5.4 24/34] Revert "net: af_key: add check for pfkey_broadcast in function pfkey_process" Sasha Levin
2022-06-07 18:00 ` [PATCH AUTOSEL 5.4 25/34] ceph: allow ceph.dir.rctime xattr to be updatable Sasha Levin
2022-06-07 18:00 ` [PATCH AUTOSEL 5.4 26/34] drm/radeon: fix a possible null pointer dereference Sasha Levin
2022-06-07 18:00 ` [PATCH AUTOSEL 5.4 27/34] modpost: fix undefined behavior of is_arm_mapping_symbol() Sasha Levin
2022-06-07 18:00 ` Sasha Levin [this message]
2022-06-07 18:00 ` [PATCH AUTOSEL 5.4 29/34] nbd: call genl_unregister_family() first in nbd_cleanup() Sasha Levin
2022-06-07 18:00 ` [PATCH AUTOSEL 5.4 30/34] nbd: fix race between nbd_alloc_config() and module removal Sasha Levin
2022-06-07 18:00 ` [PATCH AUTOSEL 5.4 31/34] nbd: fix io hung while disconnecting device Sasha Levin
2022-06-07 18:00 ` [PATCH AUTOSEL 5.4 32/34] s390/gmap: voluntarily schedule during key setting Sasha Levin
2022-06-07 18:00 ` [PATCH AUTOSEL 5.4 33/34] cifs: version operations for smb20 unneeded when legacy support disabled Sasha Levin
2022-06-07 18:00 ` [PATCH AUTOSEL 5.4 34/34] nodemask: Fix return values to be unsigned Sasha Levin

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