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> 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. 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