Revision c403f6a3a792a6601185497c12b0bdf4be880439 authored by Qian Cai on 15 August 2020, 00:31:53 UTC, committed by Linus Torvalds on 15 August 2020, 02:56:57 UTC
BUG: KCSAN: data-race in page_cpupid_xchg_last / put_page write (marked) to 0xfffffc0d48ec1a00 of 8 bytes by task 91442 on cpu 3: page_cpupid_xchg_last+0x51/0x80 page_cpupid_xchg_last at mm/mmzone.c:109 (discriminator 11) wp_page_reuse+0x3e/0xc0 wp_page_reuse at mm/memory.c:2453 do_wp_page+0x472/0x7b0 do_wp_page at mm/memory.c:2798 __handle_mm_fault+0xcb0/0xd00 handle_pte_fault at mm/memory.c:4049 (inlined by) __handle_mm_fault at mm/memory.c:4163 handle_mm_fault+0xfc/0x2f0 handle_mm_fault at mm/memory.c:4200 do_page_fault+0x263/0x6f9 do_user_addr_fault at arch/x86/mm/fault.c:1465 (inlined by) do_page_fault at arch/x86/mm/fault.c:1539 page_fault+0x34/0x40 read to 0xfffffc0d48ec1a00 of 8 bytes by task 94817 on cpu 69: put_page+0x15a/0x1f0 page_zonenum at include/linux/mm.h:923 (inlined by) is_zone_device_page at include/linux/mm.h:929 (inlined by) page_is_devmap_managed at include/linux/mm.h:948 (inlined by) put_page at include/linux/mm.h:1023 wp_page_copy+0x571/0x930 wp_page_copy at mm/memory.c:2615 do_wp_page+0x107/0x7b0 __handle_mm_fault+0xcb0/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Reported by Kernel Concurrency Sanitizer on: CPU: 69 PID: 94817 Comm: systemd-udevd Tainted: G W O L 5.5.0-next-20200204+ #6 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 A page never changes its zone number. The zone number happens to be stored in the same word as other bits which are modified, but the zone number bits will never be modified by any other write, so it can accept a reload of the zone bits after an intervening write and it don't need to use READ_ONCE(). Thus, annotate this data race using ASSERT_EXCLUSIVE_BITS() to also assert that there are no concurrent writes to it. Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Link: http://lkml.kernel.org/r/1581619089-14472-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 7e0cc01
codel.h
#ifndef __NET_SCHED_CODEL_H
#define __NET_SCHED_CODEL_H
/*
* Codel - The Controlled-Delay Active Queue Management algorithm
*
* Copyright (C) 2011-2012 Kathleen Nichols <nichols@pollere.com>
* Copyright (C) 2011-2012 Van Jacobson <van@pollere.net>
* Copyright (C) 2012 Michael D. Taht <dave.taht@bufferbloat.net>
* Copyright (C) 2012,2015 Eric Dumazet <edumazet@google.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The names of the authors may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* Alternatively, provided that this notice is retained in full, this
* software may be distributed under the terms of the GNU General
* Public License ("GPL") version 2, in which case the provisions of the
* GPL apply INSTEAD OF those given above.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*/
#include <linux/types.h>
#include <linux/ktime.h>
#include <linux/skbuff.h>
#include <net/pkt_sched.h>
#include <net/inet_ecn.h>
/* Controlling Queue Delay (CoDel) algorithm
* =========================================
* Source : Kathleen Nichols and Van Jacobson
* http://queue.acm.org/detail.cfm?id=2209336
*
* Implemented on linux by Dave Taht and Eric Dumazet
*/
/* CoDel uses a 1024 nsec clock, encoded in u32
* This gives a range of 2199 seconds, because of signed compares
*/
typedef u32 codel_time_t;
typedef s32 codel_tdiff_t;
#define CODEL_SHIFT 10
#define MS2TIME(a) ((a * NSEC_PER_MSEC) >> CODEL_SHIFT)
static inline codel_time_t codel_get_time(void)
{
u64 ns = ktime_get_ns();
return ns >> CODEL_SHIFT;
}
/* Dealing with timer wrapping, according to RFC 1982, as desc in wikipedia:
* https://en.wikipedia.org/wiki/Serial_number_arithmetic#General_Solution
* codel_time_after(a,b) returns true if the time a is after time b.
*/
#define codel_time_after(a, b) \
(typecheck(codel_time_t, a) && \
typecheck(codel_time_t, b) && \
((s32)((a) - (b)) > 0))
#define codel_time_before(a, b) codel_time_after(b, a)
#define codel_time_after_eq(a, b) \
(typecheck(codel_time_t, a) && \
typecheck(codel_time_t, b) && \
((s32)((a) - (b)) >= 0))
#define codel_time_before_eq(a, b) codel_time_after_eq(b, a)
static inline u32 codel_time_to_us(codel_time_t val)
{
u64 valns = ((u64)val << CODEL_SHIFT);
do_div(valns, NSEC_PER_USEC);
return (u32)valns;
}
/**
* struct codel_params - contains codel parameters
* @target: target queue size (in time units)
* @ce_threshold: threshold for marking packets with ECN CE
* @interval: width of moving time window
* @mtu: device mtu, or minimal queue backlog in bytes.
* @ecn: is Explicit Congestion Notification enabled
*/
struct codel_params {
codel_time_t target;
codel_time_t ce_threshold;
codel_time_t interval;
u32 mtu;
bool ecn;
};
/**
* struct codel_vars - contains codel variables
* @count: how many drops we've done since the last time we
* entered dropping state
* @lastcount: count at entry to dropping state
* @dropping: set to true if in dropping state
* @rec_inv_sqrt: reciprocal value of sqrt(count) >> 1
* @first_above_time: when we went (or will go) continuously above target
* for interval
* @drop_next: time to drop next packet, or when we dropped last
* @ldelay: sojourn time of last dequeued packet
*/
struct codel_vars {
u32 count;
u32 lastcount;
bool dropping;
u16 rec_inv_sqrt;
codel_time_t first_above_time;
codel_time_t drop_next;
codel_time_t ldelay;
};
#define REC_INV_SQRT_BITS (8 * sizeof(u16)) /* or sizeof_in_bits(rec_inv_sqrt) */
/* needed shift to get a Q0.32 number from rec_inv_sqrt */
#define REC_INV_SQRT_SHIFT (32 - REC_INV_SQRT_BITS)
/**
* struct codel_stats - contains codel shared variables and stats
* @maxpacket: largest packet we've seen so far
* @drop_count: temp count of dropped packets in dequeue()
* @drop_len: bytes of dropped packets in dequeue()
* ecn_mark: number of packets we ECN marked instead of dropping
* ce_mark: number of packets CE marked because sojourn time was above ce_threshold
*/
struct codel_stats {
u32 maxpacket;
u32 drop_count;
u32 drop_len;
u32 ecn_mark;
u32 ce_mark;
};
#define CODEL_DISABLED_THRESHOLD INT_MAX
typedef u32 (*codel_skb_len_t)(const struct sk_buff *skb);
typedef codel_time_t (*codel_skb_time_t)(const struct sk_buff *skb);
typedef void (*codel_skb_drop_t)(struct sk_buff *skb, void *ctx);
typedef struct sk_buff * (*codel_skb_dequeue_t)(struct codel_vars *vars,
void *ctx);
#endif
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