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Revision efb55222d31c8c2af8b4ba42bb56b0b0beedf98e authored by Vladimir Oltean on 30 August 2019, 01:07:21 UTC, committed by David S. Miller on 01 September 2019, 01:45:34 UTC 
taprio: Fix kernel panic in taprio_destroy
 
taprio_init may fail earlier than this line:

	list_add(&q->taprio_list, &taprio_list);

i.e. due to the net device not being multi queue.

Attempting to remove q from the global taprio_list when it is not part
of it will result in a kernel panic.

Fix it by matching list_add and list_del better to one another in the
order of operations. This way we can keep the deletion unconditional
and with lower complexity - O(1).

Cc: Leandro Dorileo <leandro.maciel.dorileo@intel.com>
Fixes: 7b9eba7ba0c1 ("net/sched: taprio: fix picos_per_byte miscalculation")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 5f81d54
Raw File
memory.c 
// SPDX-License-Identifier: GPL-2.0
/* memory.c: Prom routine for acquiring various bits of information
 *           about RAM on the machine, both virtual and physical.
 *
 * Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
 * Copyright (C) 1997 Michael A. Griffith (grif@acm.org)
 */

#include <linux/kernel.h>
#include <linux/sort.h>
#include <linux/init.h>

#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/page.h>

static int __init prom_meminit_v0(void)
{
	struct linux_mlist_v0 *p;
	int index;

	index = 0;
	for (p = *(romvec->pv_v0mem.v0_available); p; p = p->theres_more) {
		sp_banks[index].base_addr = (unsigned long) p->start_adr;
		sp_banks[index].num_bytes = p->num_bytes;
		index++;
	}

	return index;
}

static int __init prom_meminit_v2(void)
{
	struct linux_prom_registers reg[64];
	phandle node;
	int size, num_ents, i;

	node = prom_searchsiblings(prom_getchild(prom_root_node), "memory");
	size = prom_getproperty(node, "available", (char *) reg, sizeof(reg));
	num_ents = size / sizeof(struct linux_prom_registers);

	for (i = 0; i < num_ents; i++) {
		sp_banks[i].base_addr = reg[i].phys_addr;
		sp_banks[i].num_bytes = reg[i].reg_size;
	}

	return num_ents;
}

static int sp_banks_cmp(const void *a, const void *b)
{
	const struct sparc_phys_banks *x = a, *y = b;

	if (x->base_addr > y->base_addr)
		return 1;
	if (x->base_addr < y->base_addr)
		return -1;
	return 0;
}

/* Initialize the memory lists based upon the prom version. */
void __init prom_meminit(void)
{
	int i, num_ents = 0;

	switch (prom_vers) {
	case PROM_V0:
		num_ents = prom_meminit_v0();
		break;

	case PROM_V2:
	case PROM_V3:
		num_ents = prom_meminit_v2();
		break;

	default:
		break;
	}
	sort(sp_banks, num_ents, sizeof(struct sparc_phys_banks),
	     sp_banks_cmp, NULL);

	/* Sentinel.  */
	sp_banks[num_ents].base_addr = 0xdeadbeef;
	sp_banks[num_ents].num_bytes = 0;

	for (i = 0; i < num_ents; i++)
		sp_banks[i].num_bytes &= PAGE_MASK;
}
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