* [PATCH] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction
[not found] <20210712005732.4f9bfa78@zn3>
@ 2021-07-12 21:58 ` Sergei Trofimovich
2021-07-14 2:00 ` Andrew Morton
2021-07-14 3:10 ` Kees Cook
0 siblings, 2 replies; 6+ messages in thread
From: Sergei Trofimovich @ 2021-07-12 21:58 UTC (permalink / raw)
To: linux-mm
Cc: linux-kernel, Sergei Trofimovich, Andrew Morton, Kees Cook,
Alexander Potapenko, Thomas Gleixner, Vlastimil Babka,
bowsingbetee
To reproduce the failure we need the following system:
- kernel command: page_poison=1 init_on_free=0 init_on_alloc=0
- kernel config:
* CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
* CONFIG_INIT_ON_FREE_DEFAULT_ON=y
* CONFIG_PAGE_POISONING=y
0000000085629bdd: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0000000022861832: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000000c597f5b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
CPU: 11 PID: 15195 Comm: bash Kdump: loaded Tainted: G U O 5.13.1-gentoo-x86_64 #1
Hardware name: System manufacturer System Product Name/PRIME Z370-A, BIOS 2801 01/13/2021
Call Trace:
dump_stack+0x64/0x7c
__kernel_unpoison_pages.cold+0x48/0x84
post_alloc_hook+0x60/0xa0
get_page_from_freelist+0xdb8/0x1000
__alloc_pages+0x163/0x2b0
__get_free_pages+0xc/0x30
pgd_alloc+0x2e/0x1a0
? dup_mm+0x37/0x4f0
mm_init+0x185/0x270
dup_mm+0x6b/0x4f0
? __lock_task_sighand+0x35/0x70
copy_process+0x190d/0x1b10
kernel_clone+0xba/0x3b0
__do_sys_clone+0x8f/0xb0
do_syscall_64+0x68/0x80
? do_syscall_64+0x11/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Before the 51cba1eb ("init_on_alloc: Optimize static branches")
init_on_alloc never enabled static branch by default. It could
only be enabed explicitly by init_mem_debugging_and_hardening().
But after the 51cba1eb static branch could already be enabled
by default. There was no code to ever disable it. That caused
page_poison=1 / init_on_free=1 conflict.
This change extends init_mem_debugging_and_hardening() to also
disable static branch disabling.
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Kees Cook <keescook@chromium.org>
CC: Alexander Potapenko <glider@google.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Vlastimil Babka <vbabka@suse.cz>
CC: linux-mm@kvack.org
Reported-by: bowsingbetee@pm.me
Reported-by: Mikhail Morfikov
Fixes: 51cba1eb ("init_on_alloc: Optimize static branches")
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
---
mm/page_alloc.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3b97e17806be..46cb4a9c2b50 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -840,18 +840,22 @@ void init_mem_debugging_and_hardening(void)
}
#endif
- if (_init_on_alloc_enabled_early) {
- if (page_poisoning_requested)
+ if (_init_on_alloc_enabled_early ||
+ IS_ENABLED(CONFIG_INIT_ON_ALLOC_DEFAULT_ON)) {
+ if (page_poisoning_requested) {
pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
"will take precedence over init_on_alloc\n");
- else
+ static_branch_disable(&init_on_alloc);
+ } else
static_branch_enable(&init_on_alloc);
}
- if (_init_on_free_enabled_early) {
- if (page_poisoning_requested)
+ if (_init_on_free_enabled_early ||
+ IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON)) {
+ if (page_poisoning_requested) {
pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
"will take precedence over init_on_free\n");
- else
+ static_branch_disable(&init_on_free);
+ } else
static_branch_enable(&init_on_free);
}
--
2.32.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction
2021-07-12 21:58 ` [PATCH] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction Sergei Trofimovich
@ 2021-07-14 2:00 ` Andrew Morton
2021-07-17 18:18 ` Sergei Trofimovich
2021-07-14 3:10 ` Kees Cook
1 sibling, 1 reply; 6+ messages in thread
From: Andrew Morton @ 2021-07-14 2:00 UTC (permalink / raw)
To: Sergei Trofimovich
Cc: linux-mm, linux-kernel, Kees Cook, Alexander Potapenko,
Thomas Gleixner, Vlastimil Babka, bowsingbetee
On Mon, 12 Jul 2021 22:58:16 +0100 Sergei Trofimovich <slyfox@gentoo.org> wrote:
> To reproduce the failure we need the following system:
> - kernel command: page_poison=1 init_on_free=0 init_on_alloc=0
> - kernel config:
> * CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
> * CONFIG_INIT_ON_FREE_DEFAULT_ON=y
> * CONFIG_PAGE_POISONING=y
>
> 0000000085629bdd: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 0000000022861832: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 00000000c597f5b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> CPU: 11 PID: 15195 Comm: bash Kdump: loaded Tainted: G U O 5.13.1-gentoo-x86_64 #1
> Hardware name: System manufacturer System Product Name/PRIME Z370-A, BIOS 2801 01/13/2021
> Call Trace:
> dump_stack+0x64/0x7c
> __kernel_unpoison_pages.cold+0x48/0x84
> post_alloc_hook+0x60/0xa0
> get_page_from_freelist+0xdb8/0x1000
> __alloc_pages+0x163/0x2b0
> __get_free_pages+0xc/0x30
> pgd_alloc+0x2e/0x1a0
> ? dup_mm+0x37/0x4f0
> mm_init+0x185/0x270
> dup_mm+0x6b/0x4f0
> ? __lock_task_sighand+0x35/0x70
> copy_process+0x190d/0x1b10
> kernel_clone+0xba/0x3b0
> __do_sys_clone+0x8f/0xb0
> do_syscall_64+0x68/0x80
> ? do_syscall_64+0x11/0x80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Before the 51cba1eb ("init_on_alloc: Optimize static branches")
> init_on_alloc never enabled static branch by default. It could
> only be enabed explicitly by init_mem_debugging_and_hardening().
>
> But after the 51cba1eb static branch could already be enabled
> by default. There was no code to ever disable it. That caused
> page_poison=1 / init_on_free=1 conflict.
>
> This change extends init_mem_debugging_and_hardening() to also
> disable static branch disabling.
>
> ...
>
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -840,18 +840,22 @@ void init_mem_debugging_and_hardening(void)
> }
> #endif
>
> - if (_init_on_alloc_enabled_early) {
> - if (page_poisoning_requested)
> + if (_init_on_alloc_enabled_early ||
> + IS_ENABLED(CONFIG_INIT_ON_ALLOC_DEFAULT_ON)) {
> + if (page_poisoning_requested) {
> pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
> "will take precedence over init_on_alloc\n");
> - else
> + static_branch_disable(&init_on_alloc);
> + } else
> static_branch_enable(&init_on_alloc);
> }
> - if (_init_on_free_enabled_early) {
> - if (page_poisoning_requested)
> + if (_init_on_free_enabled_early ||
> + IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON)) {
> + if (page_poisoning_requested) {
> pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
> "will take precedence over init_on_free\n");
> - else
> + static_branch_disable(&init_on_free);
> + } else
> static_branch_enable(&init_on_free);
> }
>
I'm thinking this is sufficiently serious and sufficiently reported to
warrant a cc:stable backport. Agree?
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction
2021-07-12 21:58 ` [PATCH] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction Sergei Trofimovich
2021-07-14 2:00 ` Andrew Morton
@ 2021-07-14 3:10 ` Kees Cook
2021-07-14 11:11 ` bowsingbetee
1 sibling, 1 reply; 6+ messages in thread
From: Kees Cook @ 2021-07-14 3:10 UTC (permalink / raw)
To: Sergei Trofimovich
Cc: linux-mm, linux-kernel, Andrew Morton, Alexander Potapenko,
Thomas Gleixner, Vlastimil Babka, bowsingbetee
On Mon, Jul 12, 2021 at 10:58:16PM +0100, Sergei Trofimovich wrote:
> To reproduce the failure we need the following system:
> - kernel command: page_poison=1 init_on_free=0 init_on_alloc=0
> - kernel config:
> * CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
> * CONFIG_INIT_ON_FREE_DEFAULT_ON=y
> * CONFIG_PAGE_POISONING=y
>
> 0000000085629bdd: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 0000000022861832: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 00000000c597f5b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> CPU: 11 PID: 15195 Comm: bash Kdump: loaded Tainted: G U O 5.13.1-gentoo-x86_64 #1
> Hardware name: System manufacturer System Product Name/PRIME Z370-A, BIOS 2801 01/13/2021
> Call Trace:
> dump_stack+0x64/0x7c
> __kernel_unpoison_pages.cold+0x48/0x84
> post_alloc_hook+0x60/0xa0
> get_page_from_freelist+0xdb8/0x1000
> __alloc_pages+0x163/0x2b0
> __get_free_pages+0xc/0x30
> pgd_alloc+0x2e/0x1a0
> ? dup_mm+0x37/0x4f0
> mm_init+0x185/0x270
> dup_mm+0x6b/0x4f0
> ? __lock_task_sighand+0x35/0x70
> copy_process+0x190d/0x1b10
> kernel_clone+0xba/0x3b0
> __do_sys_clone+0x8f/0xb0
> do_syscall_64+0x68/0x80
> ? do_syscall_64+0x11/0x80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Before the 51cba1eb ("init_on_alloc: Optimize static branches")
> init_on_alloc never enabled static branch by default. It could
> only be enabed explicitly by init_mem_debugging_and_hardening().
But init_mem_debugging_and_hardening() is always called (by mm_init()).
> But after the 51cba1eb static branch could already be enabled
> by default. There was no code to ever disable it. That caused
> page_poison=1 / init_on_free=1 conflict.
>
> This change extends init_mem_debugging_and_hardening() to also
> disable static branch disabling.
>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: Kees Cook <keescook@chromium.org>
> CC: Alexander Potapenko <glider@google.com>
> CC: Thomas Gleixner <tglx@linutronix.de>
> CC: Vlastimil Babka <vbabka@suse.cz>
> CC: linux-mm@kvack.org
> Reported-by: bowsingbetee@pm.me
> Reported-by: Mikhail Morfikov
> Fixes: 51cba1eb ("init_on_alloc: Optimize static branches")
> Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
> ---
> mm/page_alloc.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 3b97e17806be..46cb4a9c2b50 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -840,18 +840,22 @@ void init_mem_debugging_and_hardening(void)
> }
> #endif
>
> - if (_init_on_alloc_enabled_early) {
> - if (page_poisoning_requested)
> + if (_init_on_alloc_enabled_early ||
> + IS_ENABLED(CONFIG_INIT_ON_ALLOC_DEFAULT_ON)) {
This doesn't look right. _init_on_alloc_enabled_early already has the
same value:
static bool _init_on_alloc_enabled_early __read_mostly
= IS_ENABLED(CONFIG_INIT_ON_ALLOC_DEFAULT_ON);
So checking this is just a side-effect of how static_branch_maybe()
happens to be behaving.
> + if (page_poisoning_requested) {
> pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
> "will take precedence over init_on_alloc\n");
> - else
> + static_branch_disable(&init_on_alloc);
> + } else
> static_branch_enable(&init_on_alloc);
> }
> - if (_init_on_free_enabled_early) {
> - if (page_poisoning_requested)
> + if (_init_on_free_enabled_early ||
> + IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON)) {
> + if (page_poisoning_requested) {
> pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
> "will take precedence over init_on_free\n");
> - else
> + static_branch_disable(&init_on_free);
> + } else
> static_branch_enable(&init_on_free);
> }
I think it would be better to clean this up without additional
confusion involving the CONFIGs:
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3b97e17806be..1f19365bc158 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -840,21 +840,24 @@ void init_mem_debugging_and_hardening(void)
}
#endif
- if (_init_on_alloc_enabled_early) {
- if (page_poisoning_requested)
- pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
- "will take precedence over init_on_alloc\n");
- else
- static_branch_enable(&init_on_alloc);
- }
- if (_init_on_free_enabled_early) {
- if (page_poisoning_requested)
- pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
- "will take precedence over init_on_free\n");
- else
- static_branch_enable(&init_on_free);
+ if ((_init_on_alloc_enabled_early || _init_on_free_enabled_early) &&
+ page_poisoning_requested) {
+ pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
+ "will take precedence over init_on_alloc and init_on_free\n");
+ _init_on_alloc_enabled_early = false;
+ _init_on_free_enabled_early = false;
}
+ if (_init_on_alloc_enabled_early)
+ static_branch_enable(&init_on_alloc);
+ else
+ static_branch_disable(&init_on_alloc);
+
+ if (_init_on_free_enabled_early)
+ static_branch_enable(&init_on_free);
+ else
+ static_branch_disable(&init_on_free);
+
#ifdef CONFIG_DEBUG_PAGEALLOC
if (!debug_pagealloc_enabled())
return;
--
Kees Cook
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction
2021-07-14 3:10 ` Kees Cook
@ 2021-07-14 11:11 ` bowsingbetee
2021-07-14 21:14 ` Kees Cook
0 siblings, 1 reply; 6+ messages in thread
From: bowsingbetee @ 2021-07-14 11:11 UTC (permalink / raw)
To: Kees Cook
Cc: Sergei Trofimovich, linux-mm, linux-kernel, Andrew Morton,
Alexander Potapenko, Thomas Gleixner, Vlastimil Babka
[-- Attachment #1.1: Type: text/plain, Size: 8604 bytes --]
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Wednesday, July 14th, 2021 at 5:10 AM, Kees Cook <keescook@chromium.org> wrote:
> On Mon, Jul 12, 2021 at 10:58:16PM +0100, Sergei Trofimovich wrote:
>
> > To reproduce the failure we need the following system:
> >
> > - kernel command: page_poison=1 init_on_free=0 init_on_alloc=0
> >
> > - kernel config:
> >
> > - CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
> > - CONFIG_INIT_ON_FREE_DEFAULT_ON=y
> > - CONFIG_PAGE_POISONING=y
> >
> > 0000000085629bdd: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> >
> > 0000000022861832: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> >
> > 00000000c597f5b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> >
> > CPU: 11 PID: 15195 Comm: bash Kdump: loaded Tainted: G U O 5.13.1-gentoo-x86_64 #1
> >
> > Hardware name: System manufacturer System Product Name/PRIME Z370-A, BIOS 2801 01/13/2021
> >
> > Call Trace:
> >
> > dump_stack+0x64/0x7c
> >
> > __kernel_unpoison_pages.cold+0x48/0x84
> >
> > post_alloc_hook+0x60/0xa0
> >
> > get_page_from_freelist+0xdb8/0x1000
> >
> > __alloc_pages+0x163/0x2b0
> >
> > __get_free_pages+0xc/0x30
> >
> > pgd_alloc+0x2e/0x1a0
> >
> > ? dup_mm+0x37/0x4f0
> >
> > mm_init+0x185/0x270
> >
> > dup_mm+0x6b/0x4f0
> >
> > ? __lock_task_sighand+0x35/0x70
> >
> > copy_process+0x190d/0x1b10
> >
> > kernel_clone+0xba/0x3b0
> >
> > __do_sys_clone+0x8f/0xb0
> >
> > do_syscall_64+0x68/0x80
> >
> > ? do_syscall_64+0x11/0x80
> >
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> >
> >
> > Before the 51cba1eb ("init_on_alloc: Optimize static branches")
> >
> > init_on_alloc never enabled static branch by default. It could
> >
> > only be enabed explicitly by init_mem_debugging_and_hardening().
>
> But init_mem_debugging_and_hardening() is always called (by mm_init()).
>
> > But after the 51cba1eb static branch could already be enabled
> >
> > by default. There was no code to ever disable it. That caused
> >
> > page_poison=1 / init_on_free=1 conflict.
> >
> > This change extends init_mem_debugging_and_hardening() to also
> >
> > disable static branch disabling.
> >
> > CC: Andrew Morton akpm@linux-foundation.org
> >
> > CC: Kees Cook keescook@chromium.org
> >
> > CC: Alexander Potapenko glider@google.com
> >
> > CC: Thomas Gleixner tglx@linutronix.de
> >
> > CC: Vlastimil Babka vbabka@suse.cz
> >
> > CC: linux-mm@kvack.org
> >
> > Reported-by: bowsingbetee@pm.me
> >
> > Reported-by: Mikhail Morfikov
> >
> > Fixes: 51cba1eb ("init_on_alloc: Optimize static branches")
> >
> > Signed-off-by: Sergei Trofimovich slyfox@gentoo.org
> > -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> >
> > mm/page_alloc.c | 16 ++++++++++------
> >
> > 1 file changed, 10 insertions(+), 6 deletions(-)
> >
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> >
> > index 3b97e17806be..46cb4a9c2b50 100644
> >
> > --- a/mm/page_alloc.c
> >
> > +++ b/mm/page_alloc.c
> >
> > @@ -840,18 +840,22 @@ void init_mem_debugging_and_hardening(void)
> >
> > }
> >
> > #endif
> >
> > - if (_init_on_alloc_enabled_early) {
> > - if (page_poisoning_requested)
> >
> >
> >
> > - if (_init_on_alloc_enabled_early ||
> > - IS_ENABLED(CONFIG_INIT_ON_ALLOC_DEFAULT_ON)) {
> >
> >
>
> This doesn't look right. _init_on_alloc_enabled_early already has the
>
> same value:
>
> static bool _init_on_alloc_enabled_early __read_mostly
>
> = IS_ENABLED(CONFIG_INIT_ON_ALLOC_DEFAULT_ON);
>
> So checking this is just a side-effect of how static_branch_maybe()
>
> happens to be behaving.
>
> > - if (page_poisoning_requested) {
> > pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
> > "will take precedence over init_on_alloc\\n");
> >
> >
> >
> > - else
> >
> >
> >
> > - static_branch_disable(&init_on_alloc);
> >
> >
> > - } else
> > static_branch_enable(&init_on_alloc);
> >
> >
> > }
> >
> > - if (_init_on_free_enabled_early) {
> > - if (page_poisoning_requested)
> >
> >
> >
> > - if (_init_on_free_enabled_early ||
> > - IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON)) {
> >
> >
> > - if (page_poisoning_requested) {
> > pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
> > "will take precedence over init_on_free\\n");
> >
> >
> >
> > - else
> >
> >
> >
> > - static_branch_disable(&init_on_free);
> >
> >
> > - } else
> > static_branch_enable(&init_on_free);
> >
> >
> > }
>
> I think it would be better to clean this up without additional
>
> confusion involving the CONFIGs:
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>
> index 3b97e17806be..1f19365bc158 100644
>
> --- a/mm/page_alloc.c
>
> +++ b/mm/page_alloc.c
>
> @@ -840,21 +840,24 @@ void init_mem_debugging_and_hardening(void)
>
> }
>
> #endif
>
> - if (_init_on_alloc_enabled_early) {
> - if (page_poisoning_requested)
>
>
> - pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
>
>
> - "will take precedence over init_on_alloc\\n");
>
>
> - else
>
>
> - static_branch_enable(&init_on_alloc);
>
>
> - }
> - if (_init_on_free_enabled_early) {
> - if (page_poisoning_requested)
>
>
> - pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
>
>
> - "will take precedence over init_on_free\\n");
>
>
> - else
>
>
> - static_branch_enable(&init_on_free);
>
>
>
> - if ((_init_on_alloc_enabled_early || _init_on_free_enabled_early) &&
> - page_poisoning_requested) {
>
>
> - pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
>
>
> - "will take precedence over init_on_alloc and init_on_free\\n");
>
B & C variants show this message and A does not, which is what I would expect to happen.
Tested variants:
A. "page_poison=1 init_on_free=0 init_on_alloc=0 slub_debug=P"
B. "page_poison=1 init_on_free=0 init_on_alloc=0 slub_debug=P init_on_free=1"
C. "page_poison=1 slub_debug=P"
in common:
CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
CONFIG_INIT_ON_FREE_DEFAULT_ON=y
CONFIG_PAGE_POISONING=y
CONFIG_SLUB_DEBUG=y
CONFIG_SLUB=y
(the slub parts don't matter, ignore them)
>
> - _init_on_alloc_enabled_early = false;
>
>
> - _init_on_free_enabled_early = false;
>
>
> }
> - if (_init_on_alloc_enabled_early)
> - static_branch_enable(&init_on_alloc);
>
>
> - else
> - static_branch_disable(&init_on_alloc);
>
>
>
> - if (_init_on_free_enabled_early)
> - static_branch_enable(&init_on_free);
>
>
> - else
> - static_branch_disable(&init_on_free);
>
>
>
> #ifdef CONFIG_DEBUG_PAGEALLOC
>
> if (!debug_pagealloc_enabled())
>
> return;
>
> ------------------------------------------------------------------------
>
> Kees Cook
While both patches(Sergei's, and yours) work for me, I'll be using this one for now.
Thank you for your work!
Cheers!
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction
2021-07-14 11:11 ` bowsingbetee
@ 2021-07-14 21:14 ` Kees Cook
0 siblings, 0 replies; 6+ messages in thread
From: Kees Cook @ 2021-07-14 21:14 UTC (permalink / raw)
To: bowsingbetee
Cc: Sergei Trofimovich, linux-mm, linux-kernel, Andrew Morton,
Alexander Potapenko, Thomas Gleixner, Vlastimil Babka
On Wed, Jul 14, 2021 at 11:11:18AM +0000, bowsingbetee wrote:
> B & C variants show this message and A does not, which is what I would expect to happen.
>
> Tested variants:
>
> A. "page_poison=1 init_on_free=0 init_on_alloc=0 slub_debug=P"
> B. "page_poison=1 init_on_free=0 init_on_alloc=0 slub_debug=P init_on_free=1"
> C. "page_poison=1 slub_debug=P"
>
> in common:
> CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
> CONFIG_INIT_ON_FREE_DEFAULT_ON=y
> CONFIG_PAGE_POISONING=y
> CONFIG_SLUB_DEBUG=y
> CONFIG_SLUB=y
>
> (the slub parts don't matter, ignore them)
>
> [...]
>
> While both patches(Sergei's, and yours) work for me, I'll be using this one for now.
>
> Thank you for your work!
> Cheers!
Awesome; thanks for testing it!
-Kees
--
Kees Cook
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction
2021-07-14 2:00 ` Andrew Morton
@ 2021-07-17 18:18 ` Sergei Trofimovich
0 siblings, 0 replies; 6+ messages in thread
From: Sergei Trofimovich @ 2021-07-17 18:18 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-mm, linux-kernel, Kees Cook, Alexander Potapenko,
Thomas Gleixner, Vlastimil Babka, bowsingbetee
On Tue, 13 Jul 2021 19:00:51 -0700
Andrew Morton <akpm@linux-foundation.org> wrote:
> On Mon, 12 Jul 2021 22:58:16 +0100 Sergei Trofimovich <slyfox@gentoo.org> wrote:
>
> > To reproduce the failure we need the following system:
> > - kernel command: page_poison=1 init_on_free=0 init_on_alloc=0
> > - kernel config:
> > * CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
> > * CONFIG_INIT_ON_FREE_DEFAULT_ON=y
> > * CONFIG_PAGE_POISONING=y
> >
> > 0000000085629bdd: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > 0000000022861832: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > 00000000c597f5b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > CPU: 11 PID: 15195 Comm: bash Kdump: loaded Tainted: G U O 5.13.1-gentoo-x86_64 #1
> > Hardware name: System manufacturer System Product Name/PRIME Z370-A, BIOS 2801 01/13/2021
> > Call Trace:
> > dump_stack+0x64/0x7c
> > __kernel_unpoison_pages.cold+0x48/0x84
> > post_alloc_hook+0x60/0xa0
> > get_page_from_freelist+0xdb8/0x1000
> > __alloc_pages+0x163/0x2b0
> > __get_free_pages+0xc/0x30
> > pgd_alloc+0x2e/0x1a0
> > ? dup_mm+0x37/0x4f0
> > mm_init+0x185/0x270
> > dup_mm+0x6b/0x4f0
> > ? __lock_task_sighand+0x35/0x70
> > copy_process+0x190d/0x1b10
> > kernel_clone+0xba/0x3b0
> > __do_sys_clone+0x8f/0xb0
> > do_syscall_64+0x68/0x80
> > ? do_syscall_64+0x11/0x80
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> >
> > Before the 51cba1eb ("init_on_alloc: Optimize static branches")
> > init_on_alloc never enabled static branch by default. It could
> > only be enabed explicitly by init_mem_debugging_and_hardening().
> >
> > But after the 51cba1eb static branch could already be enabled
> > by default. There was no code to ever disable it. That caused
> > page_poison=1 / init_on_free=1 conflict.
> >
> > This change extends init_mem_debugging_and_hardening() to also
> > disable static branch disabling.
> >
> > ...
> >
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -840,18 +840,22 @@ void init_mem_debugging_and_hardening(void)
> > }
> > #endif
> >
> > - if (_init_on_alloc_enabled_early) {
> > - if (page_poisoning_requested)
> > + if (_init_on_alloc_enabled_early ||
> > + IS_ENABLED(CONFIG_INIT_ON_ALLOC_DEFAULT_ON)) {
> > + if (page_poisoning_requested) {
> > pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
> > "will take precedence over init_on_alloc\n");
> > - else
> > + static_branch_disable(&init_on_alloc);
> > + } else
> > static_branch_enable(&init_on_alloc);
> > }
> > - if (_init_on_free_enabled_early) {
> > - if (page_poisoning_requested)
> > + if (_init_on_free_enabled_early ||
> > + IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON)) {
> > + if (page_poisoning_requested) {
> > pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
> > "will take precedence over init_on_free\n");
> > - else
> > + static_branch_disable(&init_on_free);
> > + } else
> > static_branch_enable(&init_on_free);
> > }
> >
>
> I'm thinking this is sufficiently serious and sufficiently reported to
> warrant a cc:stable backport. Agree?
I agree. The patch might be tricky to apply as is too far back. But current
release should be fine.
--
Sergei
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-07-17 18:18 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2021-07-12 21:58 ` [PATCH] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction Sergei Trofimovich
2021-07-14 2:00 ` Andrew Morton
2021-07-17 18:18 ` Sergei Trofimovich
2021-07-14 3:10 ` Kees Cook
2021-07-14 11:11 ` bowsingbetee
2021-07-14 21:14 ` Kees Cook
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