On 26 January 2015 at 04:00, Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote: > On Fri, Jan 23, 2015 at 10:37:46PM -0600, Nishanth Menon wrote: >> On 03:13-20150124, Kirill A. Shutemov wrote: >> > > >> On 09:39-20150123, Tyler Baker wrote: >> [...] >> > > >> > I just reviewed the boot logs for next-20150123 and there still seems >> > > >> > to be a related issue. I've been boot testing >> > > >> > multi_v7_defconfig+CONFIG_ARM_LPAE=y kernel configurations which still >> > > >> > seem broken. >> [...] >> > Okay, proof of concept patch is below. It's going to break every other >> > architecture with FIRST_USER_ADDRESS != 0, but I think it's cleaner way to >> > go. >> >> Testing on my end: >> >> just ran through this set (+ logs similar to Tyler's from my side): >> >> next-20150123 (multi_v7_defconfig == !LPAE) >> 1: BeagleBoard-X15(am57xx-evm): BOOT: PASS: http://paste.ubuntu.org.cn/2219449 >> 2: dra72x-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2219450 >> 3: dra7xx-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2219451 >> 4: omap5-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2219452 >> TOTAL = 4 boards, Booted Boards = 4, No Boot boards = 0 >> >> next-20150123-LPAE-Logging enabled[1] (multi_v7_defconfig +LPAE) >> 1: BeagleBoard-X15(am57xx-evm): BOOT: FAIL: http://paste.ubuntu.org.cn/2220938 >> 2: dra72x-evm: BOOT: FAIL: http://paste.ubuntu.org.cn/2220943 >> 3: dra7xx-evm: BOOT: FAIL: http://paste.ubuntu.org.cn/2220947 >> 4: omap5-evm: BOOT: FAIL: http://paste.ubuntu.org.cn/2220955 >> TOTAL = 4 boards, Booted Boards = 0, No Boot boards = 4 >> >> next-20150123-LPAE-new-patch [2] (multi_v7_defconfig + LPAE) >> 1: BeagleBoard-X15(am57xx-evm): BOOT: PASS: http://paste.ubuntu.org.cn/2221047 >> 2: dra72x-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221065 >> 3: dra7xx-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221069 >> 4: omap5-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221070 >> TOTAL = 4 boards, Booted Boards = 4, No Boot boards = 0 >> >> next-20150123-new-patch[2] (multi_v7_defconfig == !LPAE) >> 1: am335x-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221277 >> 2: am335x-sk: BOOT: PASS: http://paste.ubuntu.org.cn/2221278 >> 3: am437x-sk: BOOT: FAIL: http://paste.ubuntu.org.cn/2221279 (unrelated) >> 4: am43xx-epos: BOOT: PASS: http://paste.ubuntu.org.cn/2221280 >> 5: am43xx-gpevm: BOOT: PASS: http://paste.ubuntu.org.cn/2221281 >> 6: BeagleBoard-X15(am57xx-evm): BOOT: PASS: http://paste.ubuntu.org.cn/2221282 >> 7: BeagleBoard-XM: BOOT: FAIL: http://paste.ubuntu.org.cn/2221283 (unrelated) >> 8: beagleboard-vanilla: BOOT: PASS: http://paste.ubuntu.org.cn/2221284 >> 9: beaglebone-black: BOOT: PASS: http://paste.ubuntu.org.cn/2221285 >> 10: beaglebone: BOOT: FAIL: http://paste.ubuntu.org.cn/2221286 (unrelated) >> 11: dra72x-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221287 >> 12: dra7xx-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221288 >> 13: omap5-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221289 >> 14: pandaboard-es: BOOT: PASS: http://paste.ubuntu.org.cn/2221290 >> 15: pandaboard-vanilla: BOOT: PASS: http://paste.ubuntu.org.cn/2221291 >> 16: sdp4430: BOOT: PASS: http://paste.ubuntu.org.cn/2221292 >> TOTAL = 16 boards, Booted Boards = 13, No Boot boards = 3 >> >> next-20150123-new-patch[2] (omap2plus_defconfig) >> 1: am335x-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221653 >> 2: am335x-sk: BOOT: PASS: http://paste.ubuntu.org.cn/2221654 >> 3: am437x-sk: BOOT: PASS: http://paste.ubuntu.org.cn/2221656 >> 4: am43xx-epos: BOOT: PASS: http://paste.ubuntu.org.cn/2221659 >> 5: am43xx-gpevm: BOOT: PASS: http://paste.ubuntu.org.cn/2221660 >> 6: BeagleBoard-X15(am57xx-evm): BOOT: PASS: http://paste.ubuntu.org.cn/2221661 >> 7: BeagleBoard-XM: BOOT: PASS: http://paste.ubuntu.org.cn/2221670 >> 8: beagleboard-vanilla: BOOT: PASS: http://paste.ubuntu.org.cn/2221676 >> 9: beaglebone-black: BOOT: PASS: http://paste.ubuntu.org.cn/2221683 >> 10: beaglebone: BOOT: PASS: http://paste.ubuntu.org.cn/2221690 >> 11: dra72x-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221692 >> 12: dra7xx-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221695 >> 13: omap5-evm: BOOT: PASS: http://paste.ubuntu.org.cn/2221700 >> 14: pandaboard-es: BOOT: PASS: http://paste.ubuntu.org.cn/2221704 >> 15: pandaboard-vanilla: BOOT: PASS: http://paste.ubuntu.org.cn/2221707 >> 16: sdp4430: BOOT: PASS: http://paste.ubuntu.org.cn/2221713 >> TOTAL = 16 boards, Booted Boards = 16, No Boot boards = 0 > > Okay thanks. Here's proper patch. > > From 8f9845ab8d972164b700ff3e3ce53484cceb942b Mon Sep 17 00:00:00 2001 > From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> > Date: Mon, 26 Jan 2015 12:07:54 +0200 > Subject: [PATCH 1/2] mm: fix false-positive warning on exit due mm_nr_pmds(mm) > > The problem is that we check nr_ptes/nr_pmds in exit_mmap() which happens > *before* pgd_free(). And if an arch does pte/pmd allocation in pgd_alloc() > and frees them in pgd_free() we see offset in counters by the time of the > checks. > > We tried to workaround this by offsetting expected counter value > according to FIRST_USER_ADDRESS for both nr_pte and nr_pmd in > exit_mmap(). But it doesn't work in some cases: > > 1. ARM with LPAE enabled also has non-zero USER_PGTABLES_CEILING, but > upper addresses occupied with huge pmd entries, so the trick with > offsetting expected counter value will get really ugly: we will have > to apply it nr_pmds, but not nr_ptes. > > 2. Metag has non-zero FIRST_USER_ADDRESS, but doesn't do allocation > pte/pmd page tables allocation in pgd_alloc(), just setup a pgd entry > which is allocated at boot and shared accross all processes. > > The proposal is to move the check to check_mm() which happens *after* > pgd_free() and do proper accounting during pgd_alloc() and pgd_free() > which would bring counters to zero if nothing leaked. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> I've tested this patch on top of linux-next [1] on a various array of arm, arm64 and x86 hardware. I can confirm the issue with CONFIG_ARM_LPAE=y has been resolved with no additional regressions detected. The results can be found here [2]. Feel free to add: Tested-by: Tyler Baker <tyler.baker@xxxxxxxxxx> > Reported-by: Tyler Baker <tyler.baker@xxxxxxxxxx> > Tested-by: Nishanth Menon <nm@xxxxxx> > Cc: Russell King <linux@xxxxxxxxxxxxxxxx> > Cc: James Hogan <james.hogan@xxxxxxxxxx> > Cc: Guan Xuetao <gxt@xxxxxxxxxxxxxxx> > --- > arch/arm/mm/pgd.c | 4 ++++ > arch/unicore32/mm/pgd.c | 3 +++ > kernel/fork.c | 8 ++++++++ > mm/mmap.c | 5 ----- > 4 files changed, 15 insertions(+), 5 deletions(-) > > diff --git a/arch/arm/mm/pgd.c b/arch/arm/mm/pgd.c > index 249379535be2..a3681f11dd9f 100644 > --- a/arch/arm/mm/pgd.c > +++ b/arch/arm/mm/pgd.c > @@ -97,6 +97,7 @@ pgd_t *pgd_alloc(struct mm_struct *mm) > > no_pte: > pmd_free(mm, new_pmd); > + mm_dec_nr_pmds(mm); > no_pmd: > pud_free(mm, new_pud); > no_pud: > @@ -130,9 +131,11 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd_base) > pte = pmd_pgtable(*pmd); > pmd_clear(pmd); > pte_free(mm, pte); > + atomic_long_dec(&mm->nr_ptes); > no_pmd: > pud_clear(pud); > pmd_free(mm, pmd); > + mm_dec_nr_pmds(mm); > no_pud: > pgd_clear(pgd); > pud_free(mm, pud); > @@ -152,6 +155,7 @@ no_pgd: > pmd = pmd_offset(pud, 0); > pud_clear(pud); > pmd_free(mm, pmd); > + mm_dec_nr_pmds(mm); > pgd_clear(pgd); > pud_free(mm, pud); > } > diff --git a/arch/unicore32/mm/pgd.c b/arch/unicore32/mm/pgd.c > index 08b8d4295e70..1bc00d0305d4 100644 > --- a/arch/unicore32/mm/pgd.c > +++ b/arch/unicore32/mm/pgd.c > @@ -69,6 +69,7 @@ pgd_t *get_pgd_slow(struct mm_struct *mm) > > no_pte: > pmd_free(mm, new_pmd); > + mm_dec_nr_pmds(mm); > no_pmd: > free_pages((unsigned long)new_pgd, 0); > no_pgd: > @@ -96,7 +97,9 @@ void free_pgd_slow(struct mm_struct *mm, pgd_t *pgd) > pte = pmd_pgtable(*pmd); > pmd_clear(pmd); > pte_free(mm, pte); > + atomic_long_dec(&mm->nr_ptes); > pmd_free(mm, pmd); > + mm_dec_nr_pmds(mm) > free: > free_pages((unsigned long) pgd, 0); > } > diff --git a/kernel/fork.c b/kernel/fork.c > index c99098c52641..76d6f292274c 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -606,6 +606,14 @@ static void check_mm(struct mm_struct *mm) > printk(KERN_ALERT "BUG: Bad rss-counter state " > "mm:%p idx:%d val:%ld\n", mm, i, x); > } > + > + if (atomic_long_read(&mm->nr_ptes)) > + pr_alert("BUG: non-zero nr_ptes on freeing mm: %ld", > + atomic_long_read(&mm->nr_ptes)); > + if (mm_nr_pmds(mm)) > + pr_alert("BUG: non-zero nr_pmds on freeing mm: %ld", > + mm_nr_pmds(mm)); > + > #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS > VM_BUG_ON_MM(mm->pmd_huge_pte, mm); > #endif > diff --git a/mm/mmap.c b/mm/mmap.c > index 6a7d36d133fb..c5f44682c0d1 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -2851,11 +2851,6 @@ void exit_mmap(struct mm_struct *mm) > vma = remove_vma(vma); > } > vm_unacct_memory(nr_accounted); > - > - WARN_ON(atomic_long_read(&mm->nr_ptes) > > - round_up(FIRST_USER_ADDRESS, PMD_SIZE) >> PMD_SHIFT); > - WARN_ON(mm_nr_pmds(mm) > > - round_up(FIRST_USER_ADDRESS, PUD_SIZE) >> PUD_SHIFT); > } > > /* Insert vm structure into process list sorted by address > -- > Kirill A. Shutemov [1] https://git.linaro.org/people/tyler.baker/linux-next.git/shortlog/refs/heads/next-testing [2] http://kernelci.org/boot/all/job/tbaker/kernel/v3.19-rc5-5174-g384ba8a33c70/ Thanks, Tyler -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>