| Message ID | 20210714031935.4094114-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] mm: page_alloc: Fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction | expand |
On Tue, Jul 13, 2021 at 08:19:35PM -0700, Kees Cook wrote: > From: Sergei Trofimovich <slyfox@gentoo.org> > > 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: 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 <mmorfikov@gmail.com> > Fixes: 51cba1ebc60d ("init_on_alloc: Optimize static branches") > Cc: stable@vger.kernelo.org yay typo "kernelo". Andrew, are you able to clean this up, or should I send a v3? Sorry! -Kees > Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> > Link: https://lore.kernel.org/r/20210712215816.1512739-1-slyfox@gentoo.org > Co-developed-by: Kees Cook <keescook@chromium.org> > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > mm/page_alloc.c | 29 ++++++++++++++++------------- > 1 file changed, 16 insertions(+), 13 deletions(-) > > 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; > -- > 2.30.2 >
On 14.07.21 05:19, Kees Cook wrote: > From: Sergei Trofimovich <slyfox@gentoo.org> > > 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: 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 <mmorfikov@gmail.com> > Fixes: 51cba1ebc60d ("init_on_alloc: Optimize static branches") > Cc: stable@vger.kernelo.org > Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> > Link: https://lore.kernel.org/r/20210712215816.1512739-1-slyfox@gentoo.org > Co-developed-by: Kees Cook <keescook@chromium.org> > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > mm/page_alloc.c | 29 ++++++++++++++++------------- > 1 file changed, 16 insertions(+), 13 deletions(-) > > 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; > LGTM Reviewed-by: David Hildenbrand <david@redhat.com>
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;