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![Kuan-Ying Lee](/assets/img/avatar_default.png)
This GDB script prints page owner information for user to analyze the memory usage or memory corruption issue. Example output from an aarch64 system: (gdb) lx-dump-page-owner --pfn 655360 page_owner tracks the page as allocated Page last allocated via order 0, gfp_mask: 0x8, pid: 1, tgid: 1 ("swapper/0\000\000\000\000\000\000"), ts 1295948880 ns, free_ts 1011852016 ns PFN: 655360, Flags: 0x3fffc0000000000 0xffff8000086ab964 <post_alloc_hook+452>: ldp x19, x20, [sp, #16] 0xffff80000862e4e0 <split_map_pages+344>: cbnz w22, 0xffff80000862e57c <split_map_pages+500> 0xffff8000086370c4 <isolate_freepages_range+556>: mov x0, x27 0xffff8000086bc1cc <alloc_contig_range+808>: mov x24, x0 0xffff80000877d6d8 <cma_alloc+772>: mov w1, w0 0xffff8000082c8d18 <dma_alloc_from_contiguous+104>: ldr x19, [sp, #16] 0xffff8000082ce0e8 <atomic_pool_expand+208>: mov x19, x0 0xffff80000c1e41b4 <__dma_atomic_pool_init+172>: Cannot access memory at address 0xffff80000c1e41b4 0xffff80000c1e4298 <dma_atomic_pool_init+92>: Cannot access memory at address 0xffff80000c1e4298 0xffff8000080161d4 <do_one_initcall+176>: mov w21, w0 0xffff80000c1c1b50 <kernel_init_freeable+952>: Cannot access memory at address 0xffff80000c1c1b50 0xffff80000acf87dc <kernel_init+36>: bl 0xffff8000081ab100 <async_synchronize_full> 0xffff800008018d00 <ret_from_fork+16>: mrs x28, sp_el0 page last free stack trace: 0xffff8000086a6e8c <free_unref_page_prepare+796>: mov w2, w23 0xffff8000086aee1c <free_unref_page+96>: tst w0, #0xff 0xffff8000086af3f8 <__free_pages+292>: ldp x19, x20, [sp, #16] 0xffff80000c1f3214 <init_cma_reserved_pageblock+220>: Cannot access memory at address 0xffff80000c1f3214 0xffff80000c20363c <cma_init_reserved_areas+1284>: Cannot access memory at address 0xffff80000c20363c 0xffff8000080161d4 <do_one_initcall+176>: mov w21, w0 0xffff80000c1c1b50 <kernel_init_freeable+952>: Cannot access memory at address 0xffff80000c1c1b50 0xffff80000acf87dc <kernel_init+36>: bl 0xffff8000081ab100 <async_synchronize_full> 0xffff800008018d00 <ret_from_fork+16>: mrs x28, sp_el0 Link: https://lkml.kernel.org/r/20230808083020.22254-7-Kuan-Ying.Lee@mediatek.com Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com> Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Cc: Chinwen Chang <chinwen.chang@mediatek.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Qun-Wei Lin <qun-wei.lin@mediatek.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
190 lines
7.1 KiB
Python
190 lines
7.1 KiB
Python
# SPDX-License-Identifier: GPL-2.0
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#
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# Copyright (c) 2023 MediaTek Inc.
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#
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# Authors:
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# Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
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#
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import gdb
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from linux import utils, stackdepot, constants, mm
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if constants.LX_CONFIG_PAGE_OWNER:
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page_ext_t = utils.CachedType('struct page_ext')
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page_owner_t = utils.CachedType('struct page_owner')
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PAGE_OWNER_STACK_DEPTH = 16
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PAGE_EXT_OWNER = constants.LX_PAGE_EXT_OWNER
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PAGE_EXT_INVALID = 0x1
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PAGE_EXT_OWNER_ALLOCATED = constants.LX_PAGE_EXT_OWNER_ALLOCATED
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def help():
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t = """Usage: lx-dump-page-owner [Option]
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Option:
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--pfn [Decimal pfn]
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Example:
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lx-dump-page-owner --pfn 655360\n"""
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gdb.write("Unrecognized command\n")
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raise gdb.GdbError(t)
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class DumpPageOwner(gdb.Command):
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"""Dump page owner"""
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min_pfn = None
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max_pfn = None
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p_ops = None
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migrate_reason_names = None
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def __init__(self):
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super(DumpPageOwner, self).__init__("lx-dump-page-owner", gdb.COMMAND_SUPPORT)
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def invoke(self, args, from_tty):
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if not constants.LX_CONFIG_PAGE_OWNER:
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raise gdb.GdbError('CONFIG_PAGE_OWNER does not enable')
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page_owner_inited = gdb.parse_and_eval('page_owner_inited')
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if page_owner_inited['key']['enabled']['counter'] != 0x1:
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raise gdb.GdbError('page_owner_inited is not enabled')
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self.p_ops = mm.page_ops().ops
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self.get_page_owner_info()
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argv = gdb.string_to_argv(args)
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if len(argv) == 0:
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self.read_page_owner()
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elif len(argv) == 2:
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if argv[0] == "--pfn":
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pfn = int(argv[1])
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self.read_page_owner_by_addr(self.p_ops.pfn_to_page(pfn))
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else:
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help()
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else:
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help()
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def get_page_owner_info(self):
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self.min_pfn = int(gdb.parse_and_eval("min_low_pfn"))
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self.max_pfn = int(gdb.parse_and_eval("max_pfn"))
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self.page_ext_size = int(gdb.parse_and_eval("page_ext_size"))
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self.migrate_reason_names = gdb.parse_and_eval('migrate_reason_names')
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def page_ext_invalid(self, page_ext):
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if page_ext == gdb.Value(0):
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return True
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if page_ext.cast(utils.get_ulong_type()) & PAGE_EXT_INVALID == PAGE_EXT_INVALID:
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return True
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return False
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def get_entry(self, base, index):
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return (base.cast(utils.get_ulong_type()) + self.page_ext_size * index).cast(page_ext_t.get_type().pointer())
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def lookup_page_ext(self, page):
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pfn = self.p_ops.page_to_pfn(page)
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section = self.p_ops.pfn_to_section(pfn)
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page_ext = section["page_ext"]
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if self.page_ext_invalid(page_ext):
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return gdb.Value(0)
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return self.get_entry(page_ext, pfn)
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def page_ext_get(self, page):
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page_ext = self.lookup_page_ext(page)
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if page_ext != gdb.Value(0):
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return page_ext
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else:
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return gdb.Value(0)
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def get_page_owner(self, page_ext):
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addr = page_ext.cast(utils.get_ulong_type()) + gdb.parse_and_eval("page_owner_ops")["offset"].cast(utils.get_ulong_type())
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return addr.cast(page_owner_t.get_type().pointer())
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def read_page_owner_by_addr(self, struct_page_addr):
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page = gdb.Value(struct_page_addr).cast(utils.get_page_type().pointer())
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pfn = self.p_ops.page_to_pfn(page)
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if pfn < self.min_pfn or pfn > self.max_pfn or (not self.p_ops.pfn_valid(pfn)):
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gdb.write("pfn is invalid\n")
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return
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page = self.p_ops.pfn_to_page(pfn)
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page_ext = self.page_ext_get(page)
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if page_ext == gdb.Value(0):
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gdb.write("page_ext is null\n")
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return
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if not (page_ext['flags'] & (1 << PAGE_EXT_OWNER)):
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gdb.write("page_owner flag is invalid\n")
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raise gdb.GdbError('page_owner info is not present (never set?)\n')
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if mm.test_bit(PAGE_EXT_OWNER_ALLOCATED, page_ext['flags'].address):
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gdb.write('page_owner tracks the page as allocated\n')
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else:
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gdb.write('page_owner tracks the page as freed\n')
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if not (page_ext['flags'] & (1 << PAGE_EXT_OWNER_ALLOCATED)):
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gdb.write("page_owner is not allocated\n")
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try:
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page_owner = self.get_page_owner(page_ext)
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gdb.write("Page last allocated via order %d, gfp_mask: 0x%x, pid: %d, tgid: %d (%s), ts %u ns, free_ts %u ns\n" %\
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(page_owner["order"], page_owner["gfp_mask"],\
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page_owner["pid"], page_owner["tgid"], page_owner["comm"],\
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page_owner["ts_nsec"], page_owner["free_ts_nsec"]))
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gdb.write("PFN: %d, Flags: 0x%x\n" % (pfn, page['flags']))
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if page_owner["handle"] == 0:
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gdb.write('page_owner allocation stack trace missing\n')
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else:
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stackdepot.stack_depot_print(page_owner["handle"])
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if page_owner["free_handle"] == 0:
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gdb.write('page_owner free stack trace missing\n')
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else:
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gdb.write('page last free stack trace:\n')
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stackdepot.stack_depot_print(page_owner["free_handle"])
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if page_owner['last_migrate_reason'] != -1:
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gdb.write('page has been migrated, last migrate reason: %s\n' % self.migrate_reason_names[page_owner['last_migrate_reason']])
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except:
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gdb.write("\n")
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def read_page_owner(self):
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pfn = self.min_pfn
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# Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area
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while ((not self.p_ops.pfn_valid(pfn)) and (pfn & (self.p_ops.MAX_ORDER_NR_PAGES - 1))) != 0:
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pfn += 1
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while pfn < self.max_pfn:
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#
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# If the new page is in a new MAX_ORDER_NR_PAGES area,
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# validate the area as existing, skip it if not
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#
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if ((pfn & (self.p_ops.MAX_ORDER_NR_PAGES - 1)) == 0) and (not self.p_ops.pfn_valid(pfn)):
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pfn += (self.p_ops.MAX_ORDER_NR_PAGES - 1)
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continue;
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page = self.p_ops.pfn_to_page(pfn)
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page_ext = self.page_ext_get(page)
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if page_ext == gdb.Value(0):
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pfn += 1
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continue
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if not (page_ext['flags'] & (1 << PAGE_EXT_OWNER)):
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pfn += 1
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continue
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if not (page_ext['flags'] & (1 << PAGE_EXT_OWNER_ALLOCATED)):
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pfn += 1
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continue
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try:
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page_owner = self.get_page_owner(page_ext)
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gdb.write("Page allocated via order %d, gfp_mask: 0x%x, pid: %d, tgid: %d (%s), ts %u ns, free_ts %u ns\n" %\
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(page_owner["order"], page_owner["gfp_mask"],\
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page_owner["pid"], page_owner["tgid"], page_owner["comm"],\
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page_owner["ts_nsec"], page_owner["free_ts_nsec"]))
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gdb.write("PFN: %d, Flags: 0x%x\n" % (pfn, page['flags']))
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stackdepot.stack_depot_print(page_owner["handle"])
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pfn += (1 << page_owner["order"])
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continue
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except:
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gdb.write("\n")
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pfn += 1
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DumpPageOwner()
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