On Wed, 2019-06-12 at 12:37 -0700, Dan Williams wrote: > On Wed, Jun 12, 2019 at 12:16 PM Qian Cai <cai@xxxxxx> wrote: > > > > The linux-next commit "mm/sparsemem: Add helpers track active portions > > of a section at boot" [1] causes a crash below when the first kmemleak > > scan kthread kicks in. This is because kmemleak_scan() calls > > pfn_to_online_page(() which calls pfn_valid_within() instead of > > pfn_valid() on x86 due to CONFIG_HOLES_IN_ZONE=n. > > > > The commit [1] did add an additional check of pfn_section_valid() in > > pfn_valid(), but forgot to add it in the above code path. > > > > page:ffffea0002748000 is uninitialized and poisoned > > raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff > > raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff > > page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) > > ------------[ cut here ]------------ > > kernel BUG at include/linux/mm.h:1084! > > invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI > > CPU: 5 PID: 332 Comm: kmemleak Not tainted 5.2.0-rc4-next-20190612+ #6 > > Hardware name: Lenovo ThinkSystem SR530 -[7X07RCZ000]-/-[7X07RCZ000]-, > > BIOS -[TEE113T-1.00]- 07/07/2017 > > RIP: 0010:kmemleak_scan+0x6df/0xad0 > > Call Trace: > > kmemleak_scan_thread+0x9f/0xc7 > > kthread+0x1d2/0x1f0 > > ret_from_fork+0x35/0x4 > > > > [1] https://patchwork.kernel.org/patch/10977957/ > > > > Signed-off-by: Qian Cai <cai@xxxxxx> > > --- > > include/linux/memory_hotplug.h | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h > > index 0b8a5e5ef2da..f02be86077e3 100644 > > --- a/include/linux/memory_hotplug.h > > +++ b/include/linux/memory_hotplug.h > > @@ -28,6 +28,7 @@ > > unsigned long ___nr = pfn_to_section_nr(___pfn); \ > > \ > > if (___nr < NR_MEM_SECTIONS && online_section_nr(___nr) && \ > > + pfn_section_valid(__nr_to_section(___nr), pfn) && \ > > pfn_valid_within(___pfn)) \ > > ___page = pfn_to_page(___pfn); \ > > ___page; \ > > Looks ok to me: > > Acked-by: Dan Williams <dan.j.williams@xxxxxxxxx> > > ...but why is pfn_to_online_page() a multi-line macro instead of a > static inline like all the helper routines it invokes? Sigh, probably because it is a mess over there. memory_hotplug.h and mmzone.h are included each other. Converted it directly to a static inline triggers compilation errors because mmzone.h was included somewhere else and found pfn_to_online_page() needs things like pfn_valid_within() and online_section_nr() etc which are only defined later in mmzone.h. Move pfn_to_online_page() into mmzone.h triggers errors below. In file included from ./arch/x86/include/asm/page.h:76, from ./arch/x86/include/asm/thread_info.h:12, from ./include/linux/thread_info.h:38, from ./arch/x86/include/asm/preempt.h:7, from ./include/linux/preempt.h:78, from ./include/linux/spinlock.h:51, from ./include/linux/mmzone.h:8, from ./include/linux/gfp.h:6, from ./include/linux/slab.h:15, from ./include/linux/crypto.h:19, from arch/x86/kernel/asm-offsets.c:9: ./include/linux/memory_hotplug.h: In function ‘pfn_to_online_page’: ./include/asm-generic/memory_model.h:54:29: error: ‘vmemmap’ undeclared (first use in this function); did you mean ‘mem_map’? #define __pfn_to_page(pfn) (vmemmap + (pfn)) ^~~~~~~ ./include/asm-generic/memory_model.h:82:21: note: in expansion of macro ‘__pfn_to_page’ #define pfn_to_page __pfn_to_page ^~~~~~~~~~~~~ ./include/linux/memory_hotplug.h:30:10: note: in expansion of macro ‘pfn_to_page’ return pfn_to_page(pfn); ^~~~~~~~~~~ ./include/asm-generic/memory_model.h:54:29: note: each undeclared identifier is reported only once for each function it appears in #define __pfn_to_page(pfn) (vmemmap + (pfn)) ^~~~~~~ ./include/asm-generic/memory_model.h:82:21: note: in expansion of macro ‘__pfn_to_page’ #define pfn_to_page __pfn_to_page ^~~~~~~~~~~~~ ./include/linux/memory_hotplug.h:30:10: note: in expansion of macro ‘pfn_to_page’ return pfn_to_page(pfn); ^~~~~~~~~~~ make[1]: *** [scripts/Makefile.build:112: arch/x86/kernel/asm-offsets.s] Error 1
