From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH 3.4 22/25] time: Fix overflow when HZ is smaller than 60
Date: Thu, 20 Feb 2014 15:51:38 -0800 [thread overview]
Message-ID: <20140220234843.105558201@linuxfoundation.org> (raw)
In-Reply-To: <20140220234842.483343851@linuxfoundation.org>
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mikulas Patocka <mpatocka@redhat.com>
commit 80d767d770fd9c697e434fd080c2db7b5c60c6dd upstream.
When compiling for the IA-64 ski emulator, HZ is set to 32 because the
emulation is slow and we don't want to waste too many cycles processing
timers. Alpha also has an option to set HZ to 32.
This causes integer underflow in
kernel/time/jiffies.c:
kernel/time/jiffies.c:66:2: warning: large integer implicitly truncated to unsigned type [-Woverflow]
.mult = NSEC_PER_JIFFY << JIFFIES_SHIFT, /* details above */
^
This patch reduces the JIFFIES_SHIFT value to avoid the overflow.
Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1401241639100.23871@file01.intranet.prod.int.rdu2.redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/time/jiffies.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/kernel/time/jiffies.c
+++ b/kernel/time/jiffies.c
@@ -51,7 +51,13 @@
* HZ shrinks, so values greater than 8 overflow 32bits when
* HZ=100.
*/
+#if HZ < 34
+#define JIFFIES_SHIFT 6
+#elif HZ < 67
+#define JIFFIES_SHIFT 7
+#else
#define JIFFIES_SHIFT 8
+#endif
static cycle_t jiffies_read(struct clocksource *cs)
{
next prev parent reply other threads:[~2014-02-20 23:51 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-20 23:51 [PATCH 3.4 00/25] 3.4.82-stable review Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 01/25] xen-blkfront: handle backend CLOSED without CLOSING Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 02/25] fs/file.c:fdtable: avoid triggering OOMs from alloc_fdmem Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 03/25] mac80211: fix fragmentation code, particularly for encryption Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 04/25] s390/dump: Fix dump memory detection Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 05/25] s390: fix kernel crash due to linkage stack instructions Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 06/25] spi: Fix crash with double message finalisation on error handling Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 07/25] raw: test against runtime value of max_raw_minors Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 08/25] lockd: send correct lock when granting a delayed lock Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 09/25] tty: n_gsm: Fix for modems with brk in modem status control Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 10/25] staging:iio:ad799x fix error_free_irq which was freeing an irq that may not have been requested Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 12/25] USB: ftdi_sio: add Tagsys RFID Reader IDs Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 13/25] usb-storage: add unusual-devs entry for BlackBerry 9000 Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 14/25] usb-storage: restrict bcdDevice range for Super Top in Cypress ATACB Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 15/25] usb-storage: enable multi-LUN scanning when needed Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 16/25] usb: option: blacklist ZTE MF667 net interface Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 17/25] Modpost: fixed USB alias generation for ranges including 0x9 and 0xA Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 18/25] block: add cond_resched() to potentially long running ioctl discard loop Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 19/25] IB/qib: Add missing serdes init sequence Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 20/25] KVM: return an error code in kvm_vm_ioctl_register_coalesced_mmio() Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 21/25] md/raid5: Fix CPU hotplug callback registration Greg Kroah-Hartman
2014-02-20 23:51 ` Greg Kroah-Hartman [this message]
2014-02-20 23:51 ` [PATCH 3.4 23/25] power: max17040: Fix NULL pointer dereference when there is no platform_data Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 24/25] ring-buffer: Fix first commit on sub-buffer having non-zero delta Greg Kroah-Hartman
2014-02-20 23:51 ` [PATCH 3.4 25/25] genirq: Add missing irq_to_desc export for CONFIG_SPARSE_IRQ=n Greg Kroah-Hartman
2014-02-21 5:05 ` [PATCH 3.4 00/25] 3.4.82-stable review Guenter Roeck
2014-02-21 23:40 ` Shuah Khan
2014-02-22 20:45 ` Greg KH
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