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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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a3125494cf
When we loop over all queued machine check error records to pass them to the registered notifiers we use llist_for_each_entry(). But the loop calls gen_pool_free() for the entry in the body of the loop - and then the iterator looks at node->next after the free. Use llist_for_each_entry_safe() instead. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: <stable@vger.kernel.org> Cc: Gong Chen <gong.chen@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-edac <linux-edac@vger.kernel.org> Link: http://lkml.kernel.org/r/0205920@agluck-desk.sc.intel.com Link: http://lkml.kernel.org/r/1459929916-12852-4-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
100 lines
2.1 KiB
C
100 lines
2.1 KiB
C
/*
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* MCE event pool management in MCE context
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*
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* Copyright (C) 2015 Intel Corp.
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* Author: Chen, Gong <gong.chen@linux.intel.com>
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*
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* This file is licensed under GPLv2.
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*/
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#include <linux/smp.h>
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#include <linux/mm.h>
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#include <linux/genalloc.h>
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#include <linux/llist.h>
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#include "mce-internal.h"
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/*
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* printk() is not safe in MCE context. This is a lock-less memory allocator
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* used to save error information organized in a lock-less list.
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*
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* This memory pool is only to be used to save MCE records in MCE context.
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* MCE events are rare, so a fixed size memory pool should be enough. Use
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* 2 pages to save MCE events for now (~80 MCE records at most).
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*/
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#define MCE_POOLSZ (2 * PAGE_SIZE)
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static struct gen_pool *mce_evt_pool;
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static LLIST_HEAD(mce_event_llist);
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static char gen_pool_buf[MCE_POOLSZ];
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void mce_gen_pool_process(void)
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{
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struct llist_node *head;
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struct mce_evt_llist *node, *tmp;
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struct mce *mce;
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head = llist_del_all(&mce_event_llist);
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if (!head)
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return;
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head = llist_reverse_order(head);
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llist_for_each_entry_safe(node, tmp, head, llnode) {
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mce = &node->mce;
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atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
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gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));
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}
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}
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bool mce_gen_pool_empty(void)
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{
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return llist_empty(&mce_event_llist);
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}
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int mce_gen_pool_add(struct mce *mce)
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{
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struct mce_evt_llist *node;
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if (!mce_evt_pool)
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return -EINVAL;
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node = (void *)gen_pool_alloc(mce_evt_pool, sizeof(*node));
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if (!node) {
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pr_warn_ratelimited("MCE records pool full!\n");
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return -ENOMEM;
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}
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memcpy(&node->mce, mce, sizeof(*mce));
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llist_add(&node->llnode, &mce_event_llist);
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return 0;
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}
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static int mce_gen_pool_create(void)
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{
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struct gen_pool *tmpp;
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int ret = -ENOMEM;
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tmpp = gen_pool_create(ilog2(sizeof(struct mce_evt_llist)), -1);
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if (!tmpp)
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goto out;
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ret = gen_pool_add(tmpp, (unsigned long)gen_pool_buf, MCE_POOLSZ, -1);
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if (ret) {
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gen_pool_destroy(tmpp);
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goto out;
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}
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mce_evt_pool = tmpp;
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out:
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return ret;
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}
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int mce_gen_pool_init(void)
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{
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/* Just init mce_gen_pool once. */
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if (mce_evt_pool)
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return 0;
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return mce_gen_pool_create();
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}
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