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[80.7.220.175]) by smtp.gmail.com with ESMTPSA id f3-20020adfdb43000000b00236883f2f5csm19788512wrj.94.2023.01.13.09.45.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Jan 2023 09:45:53 -0800 (PST) Date: Fri, 13 Jan 2023 17:45:51 +0000 From: Daniel Thompson To: Marek Szyprowski Cc: Kefeng Wang , akpm@linux-foundation.org, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH -next 5/7] mm: memory: convert wp_page_copy() to use folios Message-ID: References: <20230112083006.163393-1-wangkefeng.wang@huawei.com> <20230112083006.163393-6-wangkefeng.wang@huawei.com> <32fefce6-e25d-106d-12ec-8fc612843cfb@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <32fefce6-e25d-106d-12ec-8fc612843cfb@samsung.com> X-Rspamd-Queue-Id: 6437D14001D X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: pezdypd3hp9eoranggccbqysjad9esd3 X-HE-Tag: 1673631955-529926 X-HE-Meta: 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 wsY+QpxH tQY1SPsk1fbYwwChCgMXXuqJ+nUWrSBK0D8NBu0mbF0KBEDiiPJvuDI2lcpXvcCITgFJBhHajSRo8pLyvIhXoYF1+QJIPtZrd9xR0VhoKO+jcFtEGgyLPd+rlIw9ePqlHY2g8 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Jan 13, 2023 at 02:01:36PM +0100, Marek Szyprowski wrote: > Hi > > On 12.01.2023 09:30, Kefeng Wang wrote: > > The old_page/new_page are converted to old_folio/new_folio in > > wp_page_copy(), then replaced related page functions to folio > > functions. > > > > Signed-off-by: Kefeng Wang > > This patch, merged into today's linux-next as commit 9ebae00c8e30 ("mm: > memory: convert wp_page_copy() to use folios"), causes serious stability > issues on my ARM based test boards. I'm seeing something very similar[1] and it bisected down to this patch. FWIW it reproduces for me using an ARCH=arm64 defconfig kernel and with the following QEMU invocation: qemu-system-aarch64 \ -M virt -cpu cortex-a57 -nographic \ -kernel arch/arm64/boot/Image -initrd rootfs.cpio.gz The rootfs I used for reproduction is here: https://fileserver.linaro.org/s/AKcrKWB2Jtyzo6g Daniel. [1]: [ 1.740416] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 [ 1.740898] Mem abort info: [ 1.741067] ESR = 0x0000000096000006 [ 1.741291] EC = 0x25: DABT (current EL), IL = 32 bits [ 1.741557] SET = 0, FnV = 0 [ 1.741734] EA = 0, S1PTW = 0 [ 1.741910] FSC = 0x06: level 2 translation fault [ 1.742161] Data abort info: [ 1.742328] ISV = 0, ISS = 0x00000006 [ 1.742533] CM = 0, WnR = 0 [ 1.742729] user pgtable: 4k pages, 48-bit VAs, pgdp=00000000447ff000 [ 1.743041] [0000000000000008] pgd=0800000044819003, p4d=0800000044819003, pud=080000004481a003, pmd=0000000000000000 [ 1.743819] Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP [ 1.744118] Modules linked in: [ 1.744353] CPU: 0 PID: 44 Comm: modprobe Not tainted 6.2.0-rc3-00294-g9ebae00c8e30 #244 [ 1.744617] Hardware name: linux,dummy-virt (DT) [ 1.744848] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 1.745045] pc : do_wp_page+0x2c4/0xd40 [ 1.745218] lr : do_wp_page+0x2bc/0xd40 [ 1.745318] sp : ffff80000822bc10 [ 1.745415] x29: ffff80000822bc10 x28: ffff60710459b100 x27: 0000000000000002 [ 1.745633] x26: ffff80000822bd28 x25: ffff607103b18000 x24: 0000000200100073 [ 1.745815] x23: ffff607104811ff0 x22: ffffc6250d418000 x21: 0000000000000000 [ 1.745986] x20: ffff607104810360 x19: ffff607104810360 x18: 0000000000000001 [ 1.746171] x17: ffff9a4bfa8fa000 x16: ffff800008004000 x15: 0000000000000000 [ 1.746363] x14: 000000000000a8a9 x13: 0000000000000004 x12: 0000000000000026 [ 1.746548] x11: 0000000000000001 x10: 0000000000000000 x9 : ffffc6250e9e7000 [ 1.746756] x8 : ffff60710459b100 x7 : 00000000412a6223 x6 : 0000000000000000 [ 1.746928] x5 : 0000000000042cc5 x4 : 0000ffff9acb8000 x3 : ffff80000822bbe4 [ 1.747095] x2 : ffff9a4bfa8fa000 x1 : ffff60710459b100 x0 : 0000000100000000 [ 1.747341] Call trace: [ 1.747431] do_wp_page+0x2c4/0xd40 [ 1.747547] __handle_mm_fault+0x704/0x1124 [ 1.747649] handle_mm_fault+0xe4/0x25c [ 1.747736] do_page_fault+0x1e8/0x4c0 [ 1.747834] do_mem_abort+0x44/0x9c [ 1.747934] el0_da+0x60/0xd4 [ 1.748020] el0t_64_sync_handler+0xac/0x120 [ 1.748134] el0t_64_sync+0x190/0x194 [ 1.748388] Code: f9403340 943cc31e f9402b55 f9400354 (f94006b6) [ 1.748767] ---[ end trace 0000000000000000 ]--- > > VFS: Mounted root (ext4 filesystem) readonly on device 179:6. > devtmpfs: mounted > Freeing unused kernel image (initmem) memory: 1024K > Run /sbin/init as init process > 8<--- cut here --- > Unable to handle kernel NULL pointer dereference at virtual address > 00000004 when read > [00000004] *pgd=00000000 > Internal error: Oops: 5 [#1] PREEMPT SMP ARM > Modules linked in: > CPU: 0 PID: 1 Comm: init Not tainted 6.2.0-rc3-00294-g9ebae00c8e30 #13254 > Hardware name: Samsung Exynos (Flattened Device Tree) > PC is at do_wp_page+0x21c/0xd48 > LR is at do_wp_page+0x1f8/0xd48 > pc : []    lr : []    psr: 60000113 > sp : f082de58  ip : 0006fff8  fp : 0000065f > r10: 00000000  r9 : 00000c73  r8 : c2b87318 > r7 : c1d78000  r6 : b6ed9000  r5 : 00000000  r4 : f082dedc > r3 : c25d0000  r2 : 00000001  r1 : c0ee9568  r0 : 00000000 > Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none > Control: 10c5387d  Table: 4363804a  DAC: 00000051 > Register r0 information: NULL pointer > Register r1 information: non-slab/vmalloc memory > Register r2 information: non-paged memory > Register r3 information: slab mm_struct start c25d0000 pointer offset 0 > size 908 > Register r4 information: 2-page vmalloc region starting at 0xf082c000 > allocated at kernel_clone+0x54/0x3e4 > Register r5 information: NULL pointer > Register r6 information: non-paged memory > Register r7 information: slab task_struct start c1d78000 pointer offset > 0 size 4032 > Register r8 information: slab vm_area_struct start c2b87318 pointer > offset 0 size 68 > Register r9 information: non-paged memory > Register r10 information: NULL pointer > Register r11 information: non-paged memory > Register r12 information: non-paged memory > Process init (pid: 1, stack limit = 0x(ptrval)) > Stack: (0xf082de58 to 0xf082e000) > ... >  do_wp_page from handle_mm_fault+0x938/0xda8 >  handle_mm_fault from do_page_fault+0x154/0x408 >  do_page_fault from do_DataAbort+0x3c/0xb0 >  do_DataAbort from __dabt_usr+0x58/0x60 > Exception stack(0xf082dfb0 to 0xf082dff8) > dfa0:                                     00000000 00000001 b6ed9060 > 00000000 > dfc0: 00000000 b6fea968 b6ed9060 00000000 b6cd4888 00000000 00000000 > 00000000 > dfe0: b6eda28c be8a9dd0 b6e6ff08 ffff0fcc 60000010 ffffffff > Code: e594a028 e58d301c e5983008 e58d3014 (e59a3004) > ---[ end trace 0000000000000000 ]--- > Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b > CPU1: stopping > CPU: 1 PID: 0 Comm: swapper/1 Tainted: G      D > 6.2.0-rc3-00294-g9ebae00c8e30 #13254 > Hardware name: Samsung Exynos (Flattened Device Tree) >  unwind_backtrace from show_stack+0x10/0x14 >  show_stack from dump_stack_lvl+0x58/0x70 >  dump_stack_lvl from do_handle_IPI+0x348/0x374 >  do_handle_IPI from ipi_handler+0x18/0x20 >  ipi_handler from handle_percpu_devid_irq+0x9c/0x170 >  handle_percpu_devid_irq from generic_handle_domain_irq+0x24/0x34 >  generic_handle_domain_irq from gic_handle_irq+0x88/0xa8 >  gic_handle_irq from generic_handle_arch_irq+0x58/0x78 >  generic_handle_arch_irq from call_with_stack+0x18/0x20 >  call_with_stack from __irq_svc+0x9c/0xd0 > Exception stack(0xf08a9ee0 to 0xf08a9f28) > ... >  __irq_svc from cpuidle_enter_state+0x318/0x3d0 >  cpuidle_enter_state from cpuidle_enter_state_coupled+0x160/0x400 >  cpuidle_enter_state_coupled from cpuidle_enter+0x3c/0x54 >  cpuidle_enter from do_idle+0x1f0/0x2b0 >  do_idle from cpu_startup_entry+0x18/0x1c >  cpu_startup_entry from secondary_start_kernel+0x1a0/0x230 >  secondary_start_kernel from 0x40101a00 > ---[ end Kernel panic - not syncing: Attempted to kill init! > exitcode=0x0000000b ]--- > > Reverting it on top of linux-next 20220113 together with aaf3f7afbf10 > ("mm: swap: remove unneeded cgroup_throttle_swaprate()") fixes the > stability issues. > > > > --- > > mm/memory.c | 47 +++++++++++++++++++++++++---------------------- > > 1 file changed, 25 insertions(+), 22 deletions(-) > > > > diff --git a/mm/memory.c b/mm/memory.c > > index b66c425b4d7c..746f485366e8 100644 > > --- a/mm/memory.c > > +++ b/mm/memory.c > > @@ -3044,7 +3044,9 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) > > struct vm_area_struct *vma = vmf->vma; > > struct mm_struct *mm = vma->vm_mm; > > struct page *old_page = vmf->page; > > + struct folio *old_folio = page_folio(old_page); > > struct page *new_page = NULL; > > + struct folio *new_folio = NULL; > > pte_t entry; > > int page_copied = 0; > > struct mmu_notifier_range range; > > @@ -3060,12 +3062,13 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) > > vmf->address); > > if (!new_page) > > goto oom; > > + new_folio = page_folio(new_page); > > } else { > > - new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, > > - vmf->address); > > - if (!new_page) > > + new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, > > + vmf->address, false); > > + if (!new_folio) > > goto oom; > > - > > + new_page = &new_folio->page; > > ret = __wp_page_copy_user(new_page, old_page, vmf); > > if (ret) { > > /* > > @@ -3075,9 +3078,9 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) > > * from the second attempt. > > * The -EHWPOISON case will not be retried. > > */ > > - put_page(new_page); > > - if (old_page) > > - put_page(old_page); > > + folio_put(new_folio); > > + if (old_folio) > > + folio_put(old_folio); > > > > delayacct_wpcopy_end(); > > return ret == -EHWPOISON ? VM_FAULT_HWPOISON : 0; > > @@ -3085,11 +3088,11 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) > > kmsan_copy_page_meta(new_page, old_page); > > } > > > > - if (mem_cgroup_charge(page_folio(new_page), mm, GFP_KERNEL)) > > + if (mem_cgroup_charge(new_folio, mm, GFP_KERNEL)) > > goto oom_free_new; > > - cgroup_throttle_swaprate(new_page, GFP_KERNEL); > > + folio_throttle_swaprate(new_folio, GFP_KERNEL); > > > > - __SetPageUptodate(new_page); > > + __folio_mark_uptodate(new_folio); > > > > mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, > > vmf->address & PAGE_MASK, > > @@ -3101,8 +3104,8 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) > > */ > > vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl); > > if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { > > - if (old_page) { > > - if (!PageAnon(old_page)) { > > + if (old_folio) { > > + if (!folio_test_anon(old_folio)) { > > dec_mm_counter(mm, mm_counter_file(old_page)); > > inc_mm_counter(mm, MM_ANONPAGES); > > } > > @@ -3130,7 +3133,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) > > */ > > ptep_clear_flush_notify(vma, vmf->address, vmf->pte); > > page_add_new_anon_rmap(new_page, vma, vmf->address); > > - lru_cache_add_inactive_or_unevictable(new_page, vma); > > + folio_add_lru_vma(new_folio, vma); > > /* > > * We call the notify macro here because, when using secondary > > * mmu page tables (such as kvm shadow page tables), we want the > > @@ -3139,7 +3142,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) > > BUG_ON(unshare && pte_write(entry)); > > set_pte_at_notify(mm, vmf->address, vmf->pte, entry); > > update_mmu_cache(vma, vmf->address, vmf->pte); > > - if (old_page) { > > + if (old_folio) { > > /* > > * Only after switching the pte to the new page may > > * we remove the mapcount here. Otherwise another > > @@ -3166,14 +3169,14 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) > > } > > > > /* Free the old page.. */ > > - new_page = old_page; > > + new_folio = old_folio; > > page_copied = 1; > > } else { > > update_mmu_tlb(vma, vmf->address, vmf->pte); > > } > > > > - if (new_page) > > - put_page(new_page); > > + if (new_folio) > > + folio_put(new_folio); > > > > pte_unmap_unlock(vmf->pte, vmf->ptl); > > /* > > @@ -3181,19 +3184,19 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) > > * the above ptep_clear_flush_notify() did already call it. > > */ > > mmu_notifier_invalidate_range_only_end(&range); > > - if (old_page) { > > + if (old_folio) { > > if (page_copied) > > free_swap_cache(old_page); > > - put_page(old_page); > > + folio_put(old_folio); > > } > > > > delayacct_wpcopy_end(); > > return 0; > > oom_free_new: > > - put_page(new_page); > > + folio_put(new_folio); > > oom: > > - if (old_page) > > - put_page(old_page); > > + if (old_folio) > > + folio_put(old_folio); > > > > delayacct_wpcopy_end(); > > return VM_FAULT_OOM; > > Best regards > -- > Marek Szyprowski, PhD > Samsung R&D Institute Poland >