leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
36e15263aa
linux/fs/proc
History
Wu Fengguang 36e15263aa kcore: add _text to KCORE_TEXT 
Extend KCORE_TEXT to cover the pages between _text and _stext, to allow
examining some important page table pages.

`readelf -a` output on x86_64 before and after patch:
	  Type           Offset             VirtAddr           PhysAddr
before    LOAD           0x00007fff8100c000 0xffffffff81009000 0x0000000000000000
after     LOAD           0x00007fff81003000 0xffffffff81000000 0x0000000000000000

The newly covered pages are:

	0xffffffff81000000 <startup_64> etc.
	0xffffffff81001000 <init_level4_pgt>
	0xffffffff81002000 <level3_ident_pgt>
	0xffffffff81003000 <level3_kernel_pgt>
	0xffffffff81004000 <level2_fixmap_pgt>
	0xffffffff81005000 <level1_fixmap_pgt>
	0xffffffff81006000 <level2_ident_pgt>
	0xffffffff81007000 <level2_kernel_pgt>
	0xffffffff81008000 <level2_spare_pgt>

Before patch, /proc/kcore shows outdated contents for the above page
table pages, for example:

	(gdb) p level3_ident_pgt
	$1 = {<text variable, no debug info>} 0xffffffff81002000 <level3_ident_pgt>
	(gdb) p/x *((pud_t *)&level3_ident_pgt)@512
	$2 = {{pud = 0x1006063}, {pud = 0x0} <repeats 511 times>}

while the real content is:

	root@hp /home/wfg# hexdump -s 0x1002000 -n 4096 /dev/mem
	1002000 6063 0100 0000 0000 8067 0000 0000 0000
	1002010 0000 0000 0000 0000 0000 0000 0000 0000
	*
	1003000

That is, on a x86_64 box with 2GB memory, we can see first-1GB / full-2GB
identity mapping before/after patch:

	(gdb) p/x *((pud_t *)&level3_ident_pgt)@512
before  $1 = {{pud = 0x1006063}, {pud = 0x0} <repeats 511 times>}
after   $1 = {{pud = 0x1006063}, {pud = 0x8067}, {pud = 0x0} <repeats 510 times>}

Obviously the content before patch is wrong.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:47 -07:00
..
array.c proc: get_nr_threads() doesn't need ->siglock any longer 2010-05-27 09:12:47 -07:00
base.c proc: cleanup: remove unused assignments 2010-05-27 09:12:47 -07:00
cmdline.c proc: switch /proc/cmdline to seq_file 2008-10-23 14:29:04 +04:00
cpuinfo.c proc: move /proc/cpuinfo code to fs/proc/cpuinfo.c 2008-10-23 15:05:11 +04:00
devices.c proc: move /proc/devices code to fs/proc/devices.c 2008-10-23 15:02:18 +04:00
generic.c proc: remove obsolete comments 2010-05-27 09:12:47 -07:00
inode.c Merge branch 'bkl/procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing 2010-05-19 17:23:28 -07:00
internal.h proc: rename de_get() to pde_get() and inline it 2009-12-16 07:19:57 -08:00
interrupts.c proc: move /proc/interrupts boilerplate code to fs/proc/interrupts.c 2008-10-23 15:15:46 +04:00
Kconfig proc: move PROC_PAGE_MONITOR to fs/proc/Kconfig 2008-10-10 04:18:57 +04:00
kcore.c kcore: add _text to KCORE_TEXT 2010-05-27 09:12:47 -07:00
kmsg.c procfs: Use generic_file_llseek in /proc/kmsg 2010-04-09 16:35:41 +02:00
loadavg.c sched, timers: cleanup avenrun users 2009-05-15 15:32:45 +02:00
Makefile proc: export statistics for softirq to /proc 2009-06-18 13:03:41 -07:00
meminfo.c hwpoison: fix/proc/meminfo alignment 2009-10-29 07:39:25 -07:00
mmu.c
nommu.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
page.c mm: export stable page flags 2009-12-16 12:19:59 +01:00
proc_devtree.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
proc_net.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
proc_sysctl.c sysctl: Don't look at ctl_name and strategy in the generic code 2009-11-11 00:53:43 -08:00
proc_tty.c proc tty: remove struct tty_operations::read_proc 2009-04-01 08:59:10 -07:00
root.c proc: cleanup: remove unused assignments 2010-05-27 09:12:47 -07:00
softirqs.c proc: export statistics for softirq to /proc 2009-06-18 13:03:41 -07:00
stat.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
task_mmu.c pagemap: add #ifdefs CONFIG_HUGETLB_PAGE on code walking hugetlb vma 2010-05-25 08:06:58 -07:00
task_nommu.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
uptime.c [PATCH] Fix idle time field in /proc/uptime 2009-09-24 10:16:24 +02:00
version.c proc: switch /proc/version to seq_file 2008-10-23 14:19:58 +04:00
vmcore.c Merge branch 'bkl/procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing 2010-05-19 17:23:28 -07:00