From 2f060190efcee2781b3ba7cb12a6876b6e024e2d Mon Sep 17 00:00:00 2001 From: Kuan-Ying Lee Date: Tue, 8 Aug 2023 16:30:16 +0800 Subject: scripts/gdb/page_owner: add page owner support 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 : ldp x19, x20, [sp, #16] 0xffff80000862e4e0 : cbnz w22, 0xffff80000862e57c 0xffff8000086370c4 : mov x0, x27 0xffff8000086bc1cc : mov x24, x0 0xffff80000877d6d8 : mov w1, w0 0xffff8000082c8d18 : ldr x19, [sp, #16] 0xffff8000082ce0e8 : mov x19, x0 0xffff80000c1e41b4 <__dma_atomic_pool_init+172>: Cannot access memory at address 0xffff80000c1e41b4 0xffff80000c1e4298 : Cannot access memory at address 0xffff80000c1e4298 0xffff8000080161d4 : mov w21, w0 0xffff80000c1c1b50 : Cannot access memory at address 0xffff80000c1c1b50 0xffff80000acf87dc : bl 0xffff8000081ab100 0xffff800008018d00 : mrs x28, sp_el0 page last free stack trace: 0xffff8000086a6e8c : mov w2, w23 0xffff8000086aee1c : tst w0, #0xff 0xffff8000086af3f8 <__free_pages+292>: ldp x19, x20, [sp, #16] 0xffff80000c1f3214 : Cannot access memory at address 0xffff80000c1f3214 0xffff80000c20363c : Cannot access memory at address 0xffff80000c20363c 0xffff8000080161d4 : mov w21, w0 0xffff80000c1c1b50 : Cannot access memory at address 0xffff80000c1c1b50 0xffff80000acf87dc : bl 0xffff8000081ab100 0xffff800008018d00 : mrs x28, sp_el0 Link: https://lkml.kernel.org/r/20230808083020.22254-7-Kuan-Ying.Lee@mediatek.com Signed-off-by: Kuan-Ying Lee Cc: AngeloGioacchino Del Regno Cc: Chinwen Chang Cc: Matthias Brugger Cc: Qun-Wei Lin Signed-off-by: Andrew Morton --- scripts/gdb/linux/constants.py.in | 7 ++ scripts/gdb/linux/page_owner.py | 190 ++++++++++++++++++++++++++++++++++++++ scripts/gdb/vmlinux-gdb.py | 1 + 3 files changed, 198 insertions(+) create mode 100644 scripts/gdb/linux/page_owner.py (limited to 'scripts/gdb') diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in index f33be26253d2..52f61d65f430 100644 --- a/scripts/gdb/linux/constants.py.in +++ b/scripts/gdb/linux/constants.py.in @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -89,6 +90,11 @@ LX_GDBPARSED(RADIX_TREE_MAP_SIZE) LX_GDBPARSED(RADIX_TREE_MAP_SHIFT) LX_GDBPARSED(RADIX_TREE_MAP_MASK) +/* linux/page_ext.h */ +if IS_BUILTIN(CONFIG_PAGE_OWNER): + LX_GDBPARSED(PAGE_EXT_OWNER) + LX_GDBPARSED(PAGE_EXT_OWNER_ALLOCATED) + /* Kernel Configs */ LX_CONFIG(CONFIG_GENERIC_CLOCKEVENTS) LX_CONFIG(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) @@ -129,3 +135,4 @@ if IS_BUILTIN(CONFIG_NUMA): LX_VALUE(CONFIG_NODES_SHIFT) LX_CONFIG(CONFIG_DEBUG_VIRTUAL) LX_CONFIG(CONFIG_STACKDEPOT) +LX_CONFIG(CONFIG_PAGE_OWNER) diff --git a/scripts/gdb/linux/page_owner.py b/scripts/gdb/linux/page_owner.py new file mode 100644 index 000000000000..844fd5d0c912 --- /dev/null +++ b/scripts/gdb/linux/page_owner.py @@ -0,0 +1,190 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright (c) 2023 MediaTek Inc. +# +# Authors: +# Kuan-Ying Lee +# + +import gdb +from linux import utils, stackdepot, constants, mm + +if constants.LX_CONFIG_PAGE_OWNER: + page_ext_t = utils.CachedType('struct page_ext') + page_owner_t = utils.CachedType('struct page_owner') + + PAGE_OWNER_STACK_DEPTH = 16 + PAGE_EXT_OWNER = constants.LX_PAGE_EXT_OWNER + PAGE_EXT_INVALID = 0x1 + PAGE_EXT_OWNER_ALLOCATED = constants.LX_PAGE_EXT_OWNER_ALLOCATED + +def help(): + t = """Usage: lx-dump-page-owner [Option] + Option: + --pfn [Decimal pfn] + Example: + lx-dump-page-owner --pfn 655360\n""" + gdb.write("Unrecognized command\n") + raise gdb.GdbError(t) + +class DumpPageOwner(gdb.Command): + """Dump page owner""" + + min_pfn = None + max_pfn = None + p_ops = None + migrate_reason_names = None + + def __init__(self): + super(DumpPageOwner, self).__init__("lx-dump-page-owner", gdb.COMMAND_SUPPORT) + + def invoke(self, args, from_tty): + if not constants.LX_CONFIG_PAGE_OWNER: + raise gdb.GdbError('CONFIG_PAGE_OWNER does not enable') + + page_owner_inited = gdb.parse_and_eval('page_owner_inited') + if page_owner_inited['key']['enabled']['counter'] != 0x1: + raise gdb.GdbError('page_owner_inited is not enabled') + + self.p_ops = mm.page_ops().ops + self.get_page_owner_info() + argv = gdb.string_to_argv(args) + if len(argv) == 0: + self.read_page_owner() + elif len(argv) == 2: + if argv[0] == "--pfn": + pfn = int(argv[1]) + self.read_page_owner_by_addr(self.p_ops.pfn_to_page(pfn)) + else: + help() + else: + help() + + def get_page_owner_info(self): + self.min_pfn = int(gdb.parse_and_eval("min_low_pfn")) + self.max_pfn = int(gdb.parse_and_eval("max_pfn")) + self.page_ext_size = int(gdb.parse_and_eval("page_ext_size")) + self.migrate_reason_names = gdb.parse_and_eval('migrate_reason_names') + + def page_ext_invalid(self, page_ext): + if page_ext == gdb.Value(0): + return True + if page_ext.cast(utils.get_ulong_type()) & PAGE_EXT_INVALID == PAGE_EXT_INVALID: + return True + return False + + def get_entry(self, base, index): + return (base.cast(utils.get_ulong_type()) + self.page_ext_size * index).cast(page_ext_t.get_type().pointer()) + + def lookup_page_ext(self, page): + pfn = self.p_ops.page_to_pfn(page) + section = self.p_ops.pfn_to_section(pfn) + page_ext = section["page_ext"] + if self.page_ext_invalid(page_ext): + return gdb.Value(0) + return self.get_entry(page_ext, pfn) + + def page_ext_get(self, page): + page_ext = self.lookup_page_ext(page) + if page_ext != gdb.Value(0): + return page_ext + else: + return gdb.Value(0) + + def get_page_owner(self, page_ext): + addr = page_ext.cast(utils.get_ulong_type()) + gdb.parse_and_eval("page_owner_ops")["offset"].cast(utils.get_ulong_type()) + return addr.cast(page_owner_t.get_type().pointer()) + + def read_page_owner_by_addr(self, struct_page_addr): + page = gdb.Value(struct_page_addr).cast(utils.get_page_type().pointer()) + pfn = self.p_ops.page_to_pfn(page) + + if pfn < self.min_pfn or pfn > self.max_pfn or (not self.p_ops.pfn_valid(pfn)): + gdb.write("pfn is invalid\n") + return + + page = self.p_ops.pfn_to_page(pfn) + page_ext = self.page_ext_get(page) + + if page_ext == gdb.Value(0): + gdb.write("page_ext is null\n") + return + + if not (page_ext['flags'] & (1 << PAGE_EXT_OWNER)): + gdb.write("page_owner flag is invalid\n") + raise gdb.GdbError('page_owner info is not present (never set?)\n') + + if mm.test_bit(PAGE_EXT_OWNER_ALLOCATED, page_ext['flags'].address): + gdb.write('page_owner tracks the page as allocated\n') + else: + gdb.write('page_owner tracks the page as freed\n') + + if not (page_ext['flags'] & (1 << PAGE_EXT_OWNER_ALLOCATED)): + gdb.write("page_owner is not allocated\n") + + try: + page_owner = self.get_page_owner(page_ext) + 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" %\ + (page_owner["order"], page_owner["gfp_mask"],\ + page_owner["pid"], page_owner["tgid"], page_owner["comm"],\ + page_owner["ts_nsec"], page_owner["free_ts_nsec"])) + gdb.write("PFN: %d, Flags: 0x%x\n" % (pfn, page['flags'])) + if page_owner["handle"] == 0: + gdb.write('page_owner allocation stack trace missing\n') + else: + stackdepot.stack_depot_print(page_owner["handle"]) + + if page_owner["free_handle"] == 0: + gdb.write('page_owner free stack trace missing\n') + else: + gdb.write('page last free stack trace:\n') + stackdepot.stack_depot_print(page_owner["free_handle"]) + if page_owner['last_migrate_reason'] != -1: + gdb.write('page has been migrated, last migrate reason: %s\n' % self.migrate_reason_names[page_owner['last_migrate_reason']]) + except: + gdb.write("\n") + + def read_page_owner(self): + pfn = self.min_pfn + + # Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area + while ((not self.p_ops.pfn_valid(pfn)) and (pfn & (self.p_ops.MAX_ORDER_NR_PAGES - 1))) != 0: + pfn += 1 + + while pfn < self.max_pfn: + # + # If the new page is in a new MAX_ORDER_NR_PAGES area, + # validate the area as existing, skip it if not + # + if ((pfn & (self.p_ops.MAX_ORDER_NR_PAGES - 1)) == 0) and (not self.p_ops.pfn_valid(pfn)): + pfn += (self.p_ops.MAX_ORDER_NR_PAGES - 1) + continue; + + page = self.p_ops.pfn_to_page(pfn) + page_ext = self.page_ext_get(page) + if page_ext == gdb.Value(0): + pfn += 1 + continue + + if not (page_ext['flags'] & (1 << PAGE_EXT_OWNER)): + pfn += 1 + continue + if not (page_ext['flags'] & (1 << PAGE_EXT_OWNER_ALLOCATED)): + pfn += 1 + continue + + try: + page_owner = self.get_page_owner(page_ext) + gdb.write("Page allocated via order %d, gfp_mask: 0x%x, pid: %d, tgid: %d (%s), ts %u ns, free_ts %u ns\n" %\ + (page_owner["order"], page_owner["gfp_mask"],\ + page_owner["pid"], page_owner["tgid"], page_owner["comm"],\ + page_owner["ts_nsec"], page_owner["free_ts_nsec"])) + gdb.write("PFN: %d, Flags: 0x%x\n" % (pfn, page['flags'])) + stackdepot.stack_depot_print(page_owner["handle"]) + pfn += (1 << page_owner["order"]) + continue + except: + gdb.write("\n") + pfn += 1 + +DumpPageOwner() diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py index 24f149694b81..89465f0de548 100644 --- a/scripts/gdb/vmlinux-gdb.py +++ b/scripts/gdb/vmlinux-gdb.py @@ -46,3 +46,4 @@ else: import linux.interrupts import linux.mm import linux.stackdepot + import linux.page_owner -- cgit