On 10.12.19 02:04, kbuild test robot wrote: > Hi David, > > I love your patch! Yet something to improve: > > [auto build test ERROR on linus/master] > [also build test ERROR on linux/master v5.5-rc1 next-20191209] > [cannot apply to mmotm/master] > [if your patch is applied to the wrong git tree, please drop us a note to help > improve the system. BTW, we also suggest to use '--base' option to specify the > base tree in git format-patch, please see https://stackoverflow.com/a/37406982] > > url: https://github.com/0day-ci/linux/commits/David-Hildenbrand/mm-fix-max_pfn-not-falling-on-section-boundary/20191210-071011 > base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 6794862a16ef41f753abd75c03a152836e4c8028 > config: i386-defconfig (attached as .config) > compiler: gcc-7 (Debian 7.5.0-1) 7.5.0 > reproduce: > # save the attached .config to linux build tree > make ARCH=i386 > > If you fix the issue, kindly add following tag > Reported-by: kbuild test robot <lkp@xxxxxxxxx> > > All errors (new ones prefixed by >>): > > In file included from include/asm-generic/bug.h:19:0, > from arch/x86/include/asm/bug.h:83, > from include/linux/bug.h:5, > from include/linux/mmdebug.h:5, > from include/linux/mm.h:9, > from include/linux/memblock.h:13, > from fs/proc/page.c:2: > fs/proc/page.c: In function 'kpagecount_read': >>> fs/proc/page.c:32:55: error: 'PAGES_PER_SECTION' undeclared (first use in this function); did you mean 'PAGE_KERNEL_IO'? > const unsigned long max_dump_pfn = round_up(max_pfn, PAGES_PER_SECTION); > ^ > include/linux/kernel.h:62:46: note: in definition of macro '__round_mask' > #define __round_mask(x, y) ((__typeof__(x))((y)-1)) > ^ > fs/proc/page.c:32:37: note: in expansion of macro 'round_up' > const unsigned long max_dump_pfn = round_up(max_pfn, PAGES_PER_SECTION); > ^~~~~~~~ > fs/proc/page.c:32:55: note: each undeclared identifier is reported only once for each function it appears in > const unsigned long max_dump_pfn = round_up(max_pfn, PAGES_PER_SECTION); > ^ > include/linux/kernel.h:62:46: note: in definition of macro '__round_mask' > #define __round_mask(x, y) ((__typeof__(x))((y)-1)) > ^ > fs/proc/page.c:32:37: note: in expansion of macro 'round_up' > const unsigned long max_dump_pfn = round_up(max_pfn, PAGES_PER_SECTION); > ^~~~~~~~ > fs/proc/page.c: In function 'kpageflags_read': > fs/proc/page.c:212:55: error: 'PAGES_PER_SECTION' undeclared (first use in this function); did you mean 'PAGE_KERNEL_IO'? > const unsigned long max_dump_pfn = round_up(max_pfn, PAGES_PER_SECTION); > ^ > include/linux/kernel.h:62:46: note: in definition of macro '__round_mask' > #define __round_mask(x, y) ((__typeof__(x))((y)-1)) > ^ > fs/proc/page.c:212:37: note: in expansion of macro 'round_up' > const unsigned long max_dump_pfn = round_up(max_pfn, PAGES_PER_SECTION); > ^~~~~~~~ > So PAGES_PER_SECTION only applies to CONFIG_SPARSEMEM. Some local function that messes with that should do the trick. Allows us to add a comment as well :) diff --git a/fs/proc/page.c b/fs/proc/page.c index e40dbfe1168e..2984df28ccea 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -21,6 +21,21 @@ #define KPMMASK (KPMSIZE - 1) #define KPMBITS (KPMSIZE * BITS_PER_BYTE) +static inline unsigned long get_max_dump_pfn(void) +{ +#ifdef CONFIG_SPARSEMEM + /* + * The memmap of early sections is completely populated and marked + * online even if max_pfn does not fall on a section boundary - + * pfn_to_online_page() will succeed on all pages. Allow inspecting + * these memmaps. + */ + return round_up(max_pfn, PAGES_PER_SECTION); +#else + return max_pfn; +#endif +} + /* /proc/kpagecount - an array exposing page counts * * Each entry is a u64 representing the corresponding @@ -29,6 +44,7 @@ static ssize_t kpagecount_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { + const unsigned long max_dump_pfn = get_max_dump_pfn(); u64 __user *out = (u64 __user *)buf; struct page *ppage; unsigned long src = *ppos; @@ -37,9 +53,11 @@ static ssize_t kpagecount_read(struct file *file, char __user *buf, u64 pcount; pfn = src / KPMSIZE; - count = min_t(size_t, count, (max_pfn * KPMSIZE) - src); if (src & KPMMASK || count & KPMMASK) return -EINVAL; + if (src >= max_dump_pfn * KPMSIZE) + return 0; + count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src); while (count > 0) { /* @@ -208,6 +226,7 @@ u64 stable_page_flags(struct page *page) static ssize_t kpageflags_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { + const unsigned long max_dump_pfn = get_max_dump_pfn(); u64 __user *out = (u64 __user *)buf; struct page *ppage; unsigned long src = *ppos; @@ -215,9 +234,11 @@ static ssize_t kpageflags_read(struct file *file, char __user *buf, ssize_t ret = 0; pfn = src / KPMSIZE; - count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src); if (src & KPMMASK || count & KPMMASK) return -EINVAL; + if (src >= max_dump_pfn * KPMSIZE) + return 0; + count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src); while (count > 0) { /* @@ -253,6 +274,7 @@ static const struct file_operations proc_kpageflags_operations = { static ssize_t kpagecgroup_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { + const unsigned long max_dump_pfn = get_max_dump_pfn(); u64 __user *out = (u64 __user *)buf; struct page *ppage; unsigned long src = *ppos; @@ -261,9 +283,11 @@ static ssize_t kpagecgroup_read(struct file *file, char __user *buf, u64 ino; pfn = src / KPMSIZE; - count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src); if (src & KPMMASK || count & KPMMASK) return -EINVAL; + if (src >= max_dump_pfn * KPMSIZE) + return 0; + count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src); while (count > 0) { /* -- 2.21.0 -- Thanks, David / dhildenb
