> On Jun 13, 2019, at 9:17 PM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > > On Thu, Jun 13, 2019 at 11:42 AM Qian Cai <cai@xxxxxx> wrote: >> >> 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. > > Ok, makes sense I had I assumed it was something horrible like that. > > Qian, can you send more details on the reproduction steps for the > failures you are seeing? Like configs and platforms you're testing. > I've tried enabling kmemleak and offlining memory and have yet to > trigger these failures. I also have a couple people willing to help me > out with tracking down the PowerPC issue, but I assume they need some > help with the reproduction as well. https://github.com/cailca/linux-mm You can see the configs for each arch there. It was reproduced on several x86 NUMA bare-metal machines HPE, Lenovo etc either Intel or AMD. Check the “test.sh”, there is a part to do offline/online will reproduce it. The powerpc is IBM 8335-GTC (ibm,witherspoon) POWER9 which is a NUMA PowerNV platform.
