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Revision 4d59b6ccf000862beed6fc0765d3209f98a8d8a2 authored by Tejun Heo on 08 February 2017, 22:30:56 UTC, committed by Linus Torvalds on 08 February 2017, 23:41:43 UTC 
cpumask: use nr_cpumask_bits for parsing functions
 
Commit 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and
parsing functions") converted both cpumask printing and parsing
functions to use nr_cpu_ids instead of nr_cpumask_bits.  While this was
okay for the printing functions as it just picked one of the two output
formats that we were alternating between depending on a kernel config,
doing the same for parsing wasn't okay.

nr_cpumask_bits can be either nr_cpu_ids or NR_CPUS.  We can always use
nr_cpu_ids but that is a variable while NR_CPUS is a constant, so it can
be more efficient to use NR_CPUS when we can get away with it.
Converting the printing functions to nr_cpu_ids makes sense because it
affects how the masks get presented to userspace and doesn't break
anything; however, using nr_cpu_ids for parsing functions can
incorrectly leave the higher bits uninitialized while reading in these
masks from userland.  As all testing and comparison functions use
nr_cpumask_bits which can be larger than nr_cpu_ids, the parsed cpumasks
can erroneously yield false negative results.

This made the taskstats interface incorrectly return -EINVAL even when
the inputs were correct.

Fix it by restoring the parse functions to use nr_cpumask_bits instead
of nr_cpu_ids.

Link: http://lkml.kernel.org/r/20170206182442.GB31078@htj.duckdns.org
Fixes: 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Martin Steigerwald <martin.steigerwald@teamix.de>
Debugged-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: <stable@vger.kernel.org>	[4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 0911d00
Raw File
pim.h 
#ifndef __LINUX_PIM_H
#define __LINUX_PIM_H

#include <linux/skbuff.h>
#include <asm/byteorder.h>

/* Message types - V1 */
#define PIM_V1_VERSION		cpu_to_be32(0x10000000)
#define PIM_V1_REGISTER		1

/* Message types - V2 */
#define PIM_VERSION		2

/* RFC7761, sec 4.9:
 *  Type
 *        Types for specific PIM messages.  PIM Types are:
 *
 *  Message Type                          Destination
 *  ---------------------------------------------------------------------
 *  0 = Hello                             Multicast to ALL-PIM-ROUTERS
 *  1 = Register                          Unicast to RP
 *  2 = Register-Stop                     Unicast to source of Register
 *                                        packet
 *  3 = Join/Prune                        Multicast to ALL-PIM-ROUTERS
 *  4 = Bootstrap                         Multicast to ALL-PIM-ROUTERS
 *  5 = Assert                            Multicast to ALL-PIM-ROUTERS
 *  6 = Graft (used in PIM-DM only)       Unicast to RPF'(S)
 *  7 = Graft-Ack (used in PIM-DM only)   Unicast to source of Graft
 *                                        packet
 *  8 = Candidate-RP-Advertisement        Unicast to Domain's BSR
 */
enum {
	PIM_TYPE_HELLO,
	PIM_TYPE_REGISTER,
	PIM_TYPE_REGISTER_STOP,
	PIM_TYPE_JOIN_PRUNE,
	PIM_TYPE_BOOTSTRAP,
	PIM_TYPE_ASSERT,
	PIM_TYPE_GRAFT,
	PIM_TYPE_GRAFT_ACK,
	PIM_TYPE_CANDIDATE_RP_ADV
};

#define PIM_NULL_REGISTER	cpu_to_be32(0x40000000)

/* RFC7761, sec 4.9:
 * The PIM header common to all PIM messages is:
 *   0                   1                   2                   3
 *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |PIM Ver| Type  |   Reserved    |           Checksum            |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
struct pimhdr {
	__u8	type;
	__u8	reserved;
	__be16	csum;
};

/* PIMv2 register message header layout (ietf-draft-idmr-pimvsm-v2-00.ps */
struct pimreghdr {
	__u8	type;
	__u8	reserved;
	__be16	csum;
	__be32	flags;
};

int pim_rcv_v1(struct sk_buff *skb);

static inline bool ipmr_pimsm_enabled(void)
{
	return IS_BUILTIN(CONFIG_IP_PIMSM_V1) || IS_BUILTIN(CONFIG_IP_PIMSM_V2);
}

static inline struct pimhdr *pim_hdr(const struct sk_buff *skb)
{
	return (struct pimhdr *)skb_transport_header(skb);
}

static inline u8 pim_hdr_version(const struct pimhdr *pimhdr)
{
	return pimhdr->type >> 4;
}

static inline u8 pim_hdr_type(const struct pimhdr *pimhdr)
{
	return pimhdr->type & 0xf;
}

/* check if the address is 224.0.0.13, RFC7761 sec 4.3.1 */
static inline bool pim_ipv4_all_pim_routers(__be32 addr)
{
	return addr == htonl(0xE000000D);
}
#endif
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