* [PATCH] proc: do not show VmExe bigger than total executable virtual memory
@ 2017-10-06 11:32 ` Konstantin Khlebnikov
0 siblings, 0 replies; 8+ messages in thread
From: Konstantin Khlebnikov @ 2017-10-06 11:32 UTC (permalink / raw)
To: linux-mm, Andrew Morton, linux-kernel
If start_code / end_code pointers are screwed then "VmExe" could be bigger
than total executable virtual memory and "VmLib" becomes negative:
VmExe: 294320 kB
VmLib: 18446744073709327564 kB
VmExe and VmLib documented as text segment and shared library code size.
Now their sum will be always equal to mm->exec_vm which sums size of
executable and not writable and not stack areas.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
fs/proc/task_mmu.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 5589b4bd4b85..d3819beb2d30 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -46,8 +46,11 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
if (hiwater_rss < mm->hiwater_rss)
hiwater_rss = mm->hiwater_rss;
- text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;
- lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;
+ /* split executable areas between text and lib */
+ text = PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK);
+ text = min(text, mm->exec_vm << PAGE_SHIFT);
+ lib = (mm->exec_vm << PAGE_SHIFT) - text;
+
swap = get_mm_counter(mm, MM_SWAPENTS);
ptes = PTRS_PER_PTE * sizeof(pte_t) * atomic_long_read(&mm->nr_ptes);
pmds = PTRS_PER_PMD * sizeof(pmd_t) * mm_nr_pmds(mm);
@@ -78,7 +81,9 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
file << (PAGE_SHIFT-10),
shmem << (PAGE_SHIFT-10),
mm->data_vm << (PAGE_SHIFT-10),
- mm->stack_vm << (PAGE_SHIFT-10), text, lib,
+ mm->stack_vm << (PAGE_SHIFT-10),
+ text >> 10,
+ lib >> 10,
ptes >> 10,
pmds >> 10,
swap << (PAGE_SHIFT-10));
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH] proc: do not show VmExe bigger than total executable virtual memory
@ 2017-10-06 11:32 ` Konstantin Khlebnikov
0 siblings, 0 replies; 8+ messages in thread
From: Konstantin Khlebnikov @ 2017-10-06 11:32 UTC (permalink / raw)
To: linux-mm, Andrew Morton, linux-kernel
If start_code / end_code pointers are screwed then "VmExe" could be bigger
than total executable virtual memory and "VmLib" becomes negative:
VmExe: 294320 kB
VmLib: 18446744073709327564 kB
VmExe and VmLib documented as text segment and shared library code size.
Now their sum will be always equal to mm->exec_vm which sums size of
executable and not writable and not stack areas.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
fs/proc/task_mmu.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 5589b4bd4b85..d3819beb2d30 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -46,8 +46,11 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
if (hiwater_rss < mm->hiwater_rss)
hiwater_rss = mm->hiwater_rss;
- text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;
- lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;
+ /* split executable areas between text and lib */
+ text = PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK);
+ text = min(text, mm->exec_vm << PAGE_SHIFT);
+ lib = (mm->exec_vm << PAGE_SHIFT) - text;
+
swap = get_mm_counter(mm, MM_SWAPENTS);
ptes = PTRS_PER_PTE * sizeof(pte_t) * atomic_long_read(&mm->nr_ptes);
pmds = PTRS_PER_PMD * sizeof(pmd_t) * mm_nr_pmds(mm);
@@ -78,7 +81,9 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
file << (PAGE_SHIFT-10),
shmem << (PAGE_SHIFT-10),
mm->data_vm << (PAGE_SHIFT-10),
- mm->stack_vm << (PAGE_SHIFT-10), text, lib,
+ mm->stack_vm << (PAGE_SHIFT-10),
+ text >> 10,
+ lib >> 10,
ptes >> 10,
pmds >> 10,
swap << (PAGE_SHIFT-10));
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
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^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] proc: do not show VmExe bigger than total executable virtual memory
2017-10-06 11:32 ` Konstantin Khlebnikov
@ 2017-10-10 22:25 ` Andrew Morton
-1 siblings, 0 replies; 8+ messages in thread
From: Andrew Morton @ 2017-10-10 22:25 UTC (permalink / raw)
To: Konstantin Khlebnikov; +Cc: linux-mm, linux-kernel
On Fri, 06 Oct 2017 14:32:34 +0300 Konstantin Khlebnikov <khlebnikov@yandex-team.ru> wrote:
> If start_code / end_code pointers are screwed then "VmExe" could be bigger
> than total executable virtual memory and "VmLib" becomes negative:
>
> VmExe: 294320 kB
> VmLib: 18446744073709327564 kB
>
> VmExe and VmLib documented as text segment and shared library code size.
>
> Now their sum will be always equal to mm->exec_vm which sums size of
> executable and not writable and not stack areas.
When does this happen? What causes start_code/end_code to get "screwed"?
When these pointers are screwed, the result of end_code-start_code can
still be wrong while not necessarily being negative, yes? In which
case we'll still display incorrect output?
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] proc: do not show VmExe bigger than total executable virtual memory
@ 2017-10-10 22:25 ` Andrew Morton
0 siblings, 0 replies; 8+ messages in thread
From: Andrew Morton @ 2017-10-10 22:25 UTC (permalink / raw)
To: Konstantin Khlebnikov; +Cc: linux-mm, linux-kernel
On Fri, 06 Oct 2017 14:32:34 +0300 Konstantin Khlebnikov <khlebnikov@yandex-team.ru> wrote:
> If start_code / end_code pointers are screwed then "VmExe" could be bigger
> than total executable virtual memory and "VmLib" becomes negative:
>
> VmExe: 294320 kB
> VmLib: 18446744073709327564 kB
>
> VmExe and VmLib documented as text segment and shared library code size.
>
> Now their sum will be always equal to mm->exec_vm which sums size of
> executable and not writable and not stack areas.
When does this happen? What causes start_code/end_code to get "screwed"?
When these pointers are screwed, the result of end_code-start_code can
still be wrong while not necessarily being negative, yes? In which
case we'll still display incorrect output?
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] proc: do not show VmExe bigger than total executable virtual memory
2017-10-10 22:25 ` Andrew Morton
@ 2017-10-11 7:00 ` Konstantin Khlebnikov
-1 siblings, 0 replies; 8+ messages in thread
From: Konstantin Khlebnikov @ 2017-10-11 7:00 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-mm, linux-kernel
On 11.10.2017 01:25, Andrew Morton wrote:
> On Fri, 06 Oct 2017 14:32:34 +0300 Konstantin Khlebnikov <khlebnikov@yandex-team.ru> wrote:
>
>> If start_code / end_code pointers are screwed then "VmExe" could be bigger
>> than total executable virtual memory and "VmLib" becomes negative:
>>
>> VmExe: 294320 kB
>> VmLib: 18446744073709327564 kB
>>
>> VmExe and VmLib documented as text segment and shared library code size.
>>
>> Now their sum will be always equal to mm->exec_vm which sums size of
>> executable and not writable and not stack areas.
>
> When does this happen? What causes start_code/end_code to get "screwed"?
I don't know exactly what happened.
I've seen this for huge (>2Gb) statically linked binary which has whole world inside.
For it start_code .. end_code range also covers one of rodata sections.
Probably this is bug in customized linker, elf loader or both.
Anyway CONFIG_CHECKPOINT_RESTORE allows to change these pointers,
thus we cannot trust them without validation.
>
> When these pointers are screwed, the result of end_code-start_code can
> still be wrong while not necessarily being negative, yes? In which
> case we'll still display incorrect output?
>
Here we split exec_vm into main code segment and libraries.
Range start_code .. end_code declared as main code segment.
In my case it's bigger than exec_vm, so libraries have to be negative.
After my patch libraries will be 0 and whole exec_vm show as VmExe.
At least sum VmExe + VmLib stays correct and both of them sane.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] proc: do not show VmExe bigger than total executable virtual memory
@ 2017-10-11 7:00 ` Konstantin Khlebnikov
0 siblings, 0 replies; 8+ messages in thread
From: Konstantin Khlebnikov @ 2017-10-11 7:00 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-mm, linux-kernel
On 11.10.2017 01:25, Andrew Morton wrote:
> On Fri, 06 Oct 2017 14:32:34 +0300 Konstantin Khlebnikov <khlebnikov@yandex-team.ru> wrote:
>
>> If start_code / end_code pointers are screwed then "VmExe" could be bigger
>> than total executable virtual memory and "VmLib" becomes negative:
>>
>> VmExe: 294320 kB
>> VmLib: 18446744073709327564 kB
>>
>> VmExe and VmLib documented as text segment and shared library code size.
>>
>> Now their sum will be always equal to mm->exec_vm which sums size of
>> executable and not writable and not stack areas.
>
> When does this happen? What causes start_code/end_code to get "screwed"?
I don't know exactly what happened.
I've seen this for huge (>2Gb) statically linked binary which has whole world inside.
For it start_code .. end_code range also covers one of rodata sections.
Probably this is bug in customized linker, elf loader or both.
Anyway CONFIG_CHECKPOINT_RESTORE allows to change these pointers,
thus we cannot trust them without validation.
>
> When these pointers are screwed, the result of end_code-start_code can
> still be wrong while not necessarily being negative, yes? In which
> case we'll still display incorrect output?
>
Here we split exec_vm into main code segment and libraries.
Range start_code .. end_code declared as main code segment.
In my case it's bigger than exec_vm, so libraries have to be negative.
After my patch libraries will be 0 and whole exec_vm show as VmExe.
At least sum VmExe + VmLib stays correct and both of them sane.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] proc: do not show VmExe bigger than total executable virtual memory
2017-10-11 7:00 ` Konstantin Khlebnikov
@ 2017-12-01 17:25 ` Vlastimil Babka
-1 siblings, 0 replies; 8+ messages in thread
From: Vlastimil Babka @ 2017-12-01 17:25 UTC (permalink / raw)
To: Konstantin Khlebnikov, Andrew Morton; +Cc: linux-mm, linux-kernel
On 10/11/2017 09:00 AM, Konstantin Khlebnikov wrote:
> On 11.10.2017 01:25, Andrew Morton wrote:
>> On Fri, 06 Oct 2017 14:32:34 +0300 Konstantin Khlebnikov <khlebnikov@yandex-team.ru> wrote:
>>
>>> If start_code / end_code pointers are screwed then "VmExe" could be bigger
>>> than total executable virtual memory and "VmLib" becomes negative:
>>>
>>> VmExe: 294320 kB
>>> VmLib: 18446744073709327564 kB
>>>
>>> VmExe and VmLib documented as text segment and shared library code size.
>>>
>>> Now their sum will be always equal to mm->exec_vm which sums size of
>>> executable and not writable and not stack areas.
>>
>> When does this happen? What causes start_code/end_code to get "screwed"?
>
> I don't know exactly what happened.
> I've seen this for huge (>2Gb) statically linked binary which has whole world inside.
>
> For it start_code .. end_code range also covers one of rodata sections.
> Probably this is bug in customized linker, elf loader or both.
>
> Anyway CONFIG_CHECKPOINT_RESTORE allows to change these pointers,
> thus we cannot trust them without validation.
Please add this to changelog. I agree that it's better/safer after your
patch. These counters are fundamentally heuristics so we can't guarantee
"proper" values for weird binaries. exec_vm OTOH is an objective value
so it makes sense to use it as a safe boundary.
Acked-by: Vlastimil Babka <vbabka@suse.cz>
>>
>> When these pointers are screwed, the result of end_code-start_code can
>> still be wrong while not necessarily being negative, yes? In which
>> case we'll still display incorrect output?
>>
>
> Here we split exec_vm into main code segment and libraries.
>
> Range start_code .. end_code declared as main code segment.
> In my case it's bigger than exec_vm, so libraries have to be negative.
>
> After my patch libraries will be 0 and whole exec_vm show as VmExe.
> At least sum VmExe + VmLib stays correct and both of them sane.
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] proc: do not show VmExe bigger than total executable virtual memory
@ 2017-12-01 17:25 ` Vlastimil Babka
0 siblings, 0 replies; 8+ messages in thread
From: Vlastimil Babka @ 2017-12-01 17:25 UTC (permalink / raw)
To: Konstantin Khlebnikov, Andrew Morton; +Cc: linux-mm, linux-kernel
On 10/11/2017 09:00 AM, Konstantin Khlebnikov wrote:
> On 11.10.2017 01:25, Andrew Morton wrote:
>> On Fri, 06 Oct 2017 14:32:34 +0300 Konstantin Khlebnikov <khlebnikov@yandex-team.ru> wrote:
>>
>>> If start_code / end_code pointers are screwed then "VmExe" could be bigger
>>> than total executable virtual memory and "VmLib" becomes negative:
>>>
>>> VmExe: 294320 kB
>>> VmLib: 18446744073709327564 kB
>>>
>>> VmExe and VmLib documented as text segment and shared library code size.
>>>
>>> Now their sum will be always equal to mm->exec_vm which sums size of
>>> executable and not writable and not stack areas.
>>
>> When does this happen? What causes start_code/end_code to get "screwed"?
>
> I don't know exactly what happened.
> I've seen this for huge (>2Gb) statically linked binary which has whole world inside.
>
> For it start_code .. end_code range also covers one of rodata sections.
> Probably this is bug in customized linker, elf loader or both.
>
> Anyway CONFIG_CHECKPOINT_RESTORE allows to change these pointers,
> thus we cannot trust them without validation.
Please add this to changelog. I agree that it's better/safer after your
patch. These counters are fundamentally heuristics so we can't guarantee
"proper" values for weird binaries. exec_vm OTOH is an objective value
so it makes sense to use it as a safe boundary.
Acked-by: Vlastimil Babka <vbabka@suse.cz>
>>
>> When these pointers are screwed, the result of end_code-start_code can
>> still be wrong while not necessarily being negative, yes? In which
>> case we'll still display incorrect output?
>>
>
> Here we split exec_vm into main code segment and libraries.
>
> Range start_code .. end_code declared as main code segment.
> In my case it's bigger than exec_vm, so libraries have to be negative.
>
> After my patch libraries will be 0 and whole exec_vm show as VmExe.
> At least sum VmExe + VmLib stays correct and both of them sane.
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2017-12-01 17:26 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-10-06 11:32 [PATCH] proc: do not show VmExe bigger than total executable virtual memory Konstantin Khlebnikov
2017-10-06 11:32 ` Konstantin Khlebnikov
2017-10-10 22:25 ` Andrew Morton
2017-10-10 22:25 ` Andrew Morton
2017-10-11 7:00 ` Konstantin Khlebnikov
2017-10-11 7:00 ` Konstantin Khlebnikov
2017-12-01 17:25 ` Vlastimil Babka
2017-12-01 17:25 ` Vlastimil Babka
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