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![Jaewon Kim](/assets/img/avatar_default.png)
Even on 64 bit kernel, the mmap failure can happen for a 32 bit task. Virtual memory space shortage of a task on mmap is reported to userspace as -ENOMEM. It can be confused as physical memory shortage of overall system. The vm_unmapped_area can be called to by some drivers or other kernel core system like filesystem. In my platform, GPU driver calls to vm_unmapped_area and the driver returns -ENOMEM even in GPU side shortage. It can be hard to distinguish which code layer returns the -ENOMEM. Create mmap trace file and add trace point of vm_unmapped_area. i.e.) 277.156599: vm_unmapped_area: addr=77e0d03000 err=0 total_vm=0x17014b flags=0x1 len=0x400000 lo=0x8000 hi=0x7878c27000 mask=0x0 ofs=0x1 342.838740: vm_unmapped_area: addr=0 err=-12 total_vm=0xffb08 flags=0x0 len=0x100000 lo=0x40000000 hi=0xfffff000 mask=0x0 ofs=0x22 [akpm@linux-foundation.org: prefix address printk with 0x, per Matthew] Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@suse.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200320055823.27089-3-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
48 lines
1.4 KiB
C
48 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#undef TRACE_SYSTEM
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#define TRACE_SYSTEM mmap
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#if !defined(_TRACE_MMAP_H) || defined(TRACE_HEADER_MULTI_READ)
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#define _TRACE_MMAP_H
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#include <linux/tracepoint.h>
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TRACE_EVENT(vm_unmapped_area,
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TP_PROTO(unsigned long addr, struct vm_unmapped_area_info *info),
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TP_ARGS(addr, info),
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TP_STRUCT__entry(
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__field(unsigned long, addr)
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__field(unsigned long, total_vm)
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__field(unsigned long, flags)
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__field(unsigned long, length)
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__field(unsigned long, low_limit)
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__field(unsigned long, high_limit)
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__field(unsigned long, align_mask)
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__field(unsigned long, align_offset)
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),
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TP_fast_assign(
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__entry->addr = addr;
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__entry->total_vm = current->mm->total_vm;
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__entry->flags = info->flags;
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__entry->length = info->length;
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__entry->low_limit = info->low_limit;
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__entry->high_limit = info->high_limit;
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__entry->align_mask = info->align_mask;
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__entry->align_offset = info->align_offset;
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),
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TP_printk("addr=0x%lx err=%ld total_vm=0x%lx flags=0x%lx len=0x%lx lo=0x%lx hi=0x%lx mask=0x%lx ofs=0x%lx\n",
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IS_ERR_VALUE(__entry->addr) ? 0 : __entry->addr,
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IS_ERR_VALUE(__entry->addr) ? __entry->addr : 0,
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__entry->total_vm, __entry->flags, __entry->length,
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__entry->low_limit, __entry->high_limit, __entry->align_mask,
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__entry->align_offset)
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);
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#endif
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/* This part must be outside protection */
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#include <trace/define_trace.h>
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