8495f7e673
When a user process exits, the kernel cleans up the mm_struct of the user process and during cleanup, check_mm() checks the page tables of the user process for corruption (E.g: unexpected page flags set/cleared). For corrupted page tables, the error message printed by check_mm() isn't very clear as it prints the loop index instead of page table type (E.g: Resident file mapping pages vs Resident shared memory pages). The loop index in check_mm() is used to index rss_stat[] which represents individual memory type stats. Hence, instead of printing index, print memory type, thereby improving error message. Without patch: -------------- [ 204.836425] mm/pgtable-generic.c:29: bad p4d 0000000089eb4e92(800000025f941467) [ 204.836544] BUG: Bad rss-counter state mm:00000000f75895ea idx:0 val:2 [ 204.836615] BUG: Bad rss-counter state mm:00000000f75895ea idx:1 val:5 [ 204.836685] BUG: non-zero pgtables_bytes on freeing mm: 20480 With patch: ----------- [ 69.815453] mm/pgtable-generic.c:29: bad p4d 0000000084653642(800000025ca37467) [ 69.815872] BUG: Bad rss-counter state mm:00000000014a6c03 type:MM_FILEPAGES val:2 [ 69.815962] BUG: Bad rss-counter state mm:00000000014a6c03 type:MM_ANONPAGES val:5 [ 69.816050] BUG: non-zero pgtables_bytes on freeing mm: 20480 Also, change print function (from printk(KERN_ALERT, ..) to pr_alert()) so that it matches the other print statement. Link: http://lkml.kernel.org/r/da75b5153f617f4c5739c08ee6ebeb3d19db0fbc.1565123758.git.sai.praneeth.prakhya@intel.com Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Suggested-by: Dave Hansen <dave.hansen@intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Dave Hansen <dave.hansen@intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
100 lines
2.5 KiB
C
100 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_MM_TYPES_TASK_H
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#define _LINUX_MM_TYPES_TASK_H
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/*
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* Here are the definitions of the MM data types that are embedded in 'struct task_struct'.
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*
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* (These are defined separately to decouple sched.h from mm_types.h as much as possible.)
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*/
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#include <linux/types.h>
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#include <linux/threads.h>
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#include <linux/atomic.h>
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#include <linux/cpumask.h>
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#include <asm/page.h>
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#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
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#include <asm/tlbbatch.h>
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#endif
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#define USE_SPLIT_PTE_PTLOCKS (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
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#define USE_SPLIT_PMD_PTLOCKS (USE_SPLIT_PTE_PTLOCKS && \
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IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK))
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#define ALLOC_SPLIT_PTLOCKS (SPINLOCK_SIZE > BITS_PER_LONG/8)
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/*
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* The per task VMA cache array:
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*/
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#define VMACACHE_BITS 2
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#define VMACACHE_SIZE (1U << VMACACHE_BITS)
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#define VMACACHE_MASK (VMACACHE_SIZE - 1)
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struct vmacache {
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u64 seqnum;
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struct vm_area_struct *vmas[VMACACHE_SIZE];
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};
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/*
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* When updating this, please also update struct resident_page_types[] in
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* kernel/fork.c
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*/
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enum {
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MM_FILEPAGES, /* Resident file mapping pages */
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MM_ANONPAGES, /* Resident anonymous pages */
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MM_SWAPENTS, /* Anonymous swap entries */
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MM_SHMEMPAGES, /* Resident shared memory pages */
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NR_MM_COUNTERS
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};
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#if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU)
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#define SPLIT_RSS_COUNTING
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/* per-thread cached information, */
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struct task_rss_stat {
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int events; /* for synchronization threshold */
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int count[NR_MM_COUNTERS];
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};
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#endif /* USE_SPLIT_PTE_PTLOCKS */
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struct mm_rss_stat {
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atomic_long_t count[NR_MM_COUNTERS];
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};
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struct page_frag {
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struct page *page;
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#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
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__u32 offset;
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__u32 size;
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#else
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__u16 offset;
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__u16 size;
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#endif
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};
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/* Track pages that require TLB flushes */
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struct tlbflush_unmap_batch {
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#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
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/*
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* The arch code makes the following promise: generic code can modify a
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* PTE, then call arch_tlbbatch_add_mm() (which internally provides all
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* needed barriers), then call arch_tlbbatch_flush(), and the entries
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* will be flushed on all CPUs by the time that arch_tlbbatch_flush()
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* returns.
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*/
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struct arch_tlbflush_unmap_batch arch;
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/* True if a flush is needed. */
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bool flush_required;
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/*
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* If true then the PTE was dirty when unmapped. The entry must be
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* flushed before IO is initiated or a stale TLB entry potentially
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* allows an update without redirtying the page.
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*/
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bool writable;
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#endif
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};
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#endif /* _LINUX_MM_TYPES_TASK_H */
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