* [PATCH] mm: get rid of WARN if failed to cow user pages
@ 2019-12-25 5:42 Murphy Zhou
2019-12-25 8:17 ` Justin He
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Murphy Zhou @ 2019-12-25 5:42 UTC (permalink / raw)
To: linux-nvdimm, Jia He, Ross Zwisler
By running xfstests with fsdax enabled, generic/437 always hits this
warning[1] since this commit:
commit 83d116c53058d505ddef051e90ab27f57015b025
Author: Jia He <justin.he@arm.com>
Date: Fri Oct 11 22:09:39 2019 +0800
mm: fix double page fault on arm64 if PTE_AF is cleared
Looking at the test program[2] generic/437 uses, it's pretty easy
to hit this warning. Remove this WARN as it seems not necessary.
[2] https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/tree/src/t_mmap_cow_race.c
[1] warning message:
-----------------------------------------------------------------------
[ 97.344077] WARNING: CPU: 0 PID: 2486 at mm/memory.c:2281 wp_page_copy+0x687/0x6e0
[ 97.348354] Modules linked in: nf_tables nfnetlink rfkill sunrpc snd_hda_codec_generic ledtrig_audio qxl snd_hda_intel snd_intel_dspcfg drm_ttm_helper snd_hda_codec ttm snd_hda_core drm_kms_helper snd_hwdep snd_seq syscopyarea sysfillrect sysimgblt snd_seq_device fb_sys_fops snd_pcm drm snd_timer crc32_pclmul snd soundcore dax_pmem_compat i2c_piix4 device_dax virtio_balloon pcspkr joydev dax_pmem_core ip_tables xfs libcrc32c crct10dif_pclmul crc32c_intel sd_mod sg ata_generic 8139too ata_piix libata ghash_clmulni_intel 8139cp virtio_console serio_raw nd_pmem mii dm_mirror dm_region_hash dm_log dm_mod
[ 97.382176] CPU: 0 PID: 2486 Comm: t_mmap_cow_race Tainted: G W 5.5.0-rc3-v5.5-rc3 #1
[ 97.387804] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[ 97.392228] RIP: 0010:wp_page_copy+0x687/0x6e0
[ 97.396572] Code: 95 f5 00 48 81 e6 00 f0 ff ff ba 00 10 00 00 49 c1 ff 06 49 c1 e7 0c 4c 03 3d 35 95 f5 00 4c 89 ff e8 8d 85 6a 00 85 c0 74 0a <0f> 0b 4c 89 ff e8 8f 80 6a 00 65 48 8b 04 25 40 7f 01 00 83 a8 d8
[ 97.413487] RSP: 0000:ffffb882493afd28 EFLAGS: 00010206
[ 97.417520] RAX: 0000000000001000 RBX: ffffb882493afdf8 RCX: 0000000000001000
[ 97.422295] RDX: 0000000000001000 RSI: 00007f1d20c00000 RDI: ffff976384d1f000
[ 97.426914] RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000ca308
[ 97.431746] R10: 0000000000000000 R11: ffffe0cd4c1347c0 R12: ffffe0cd4c1347c0
[ 97.436371] R13: ffff9763b46ba190 R14: ffff9763a963d0c0 R15: ffff976384d1f000
[ 97.441085] FS: 00007f1d203fe700(0000) GS:ffff9763b8a00000(0000) knlGS:0000000000000000
[ 97.445500] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 97.448393] CR2: 00007f1d20c00000 CR3: 0000000333dfc000 CR4: 00000000000006f0
[ 97.452346] Call Trace:
[ 97.453681] ? __switch_to_asm+0x34/0x70
[ 97.455566] ? __switch_to_asm+0x40/0x70
[ 97.457418] ? __switch_to_asm+0x34/0x70
[ 97.459197] ? __switch_to_asm+0x40/0x70
[ 97.460971] ? __switch_to_asm+0x34/0x70
[ 97.462746] ? __switch_to_asm+0x40/0x70
[ 97.464561] ? __switch_to_asm+0x34/0x70
[ 97.466342] ? __switch_to_asm+0x40/0x70
[ 97.468141] do_wp_page+0x8c/0x640
[ 97.469818] ? finish_task_switch+0x77/0x2a0
[ 97.471631] __handle_mm_fault+0xa06/0x1420
[ 97.473517] handle_mm_fault+0xae/0x1d0
[ 97.475168] __do_page_fault+0x27f/0x4e0
[ 97.476947] do_page_fault+0x30/0x110
[ 97.478490] async_page_fault+0x39/0x40
[ 97.480275] RIP: 0033:0x400d68
[ 97.481587] Code: 53 48 89 fb 48 83 ec 10 66 2e 0f 1f 84 00 00 00 00 00 0f b6 03 ba 04 00 00 00 be 00 00 20 00 48 89 df 89 44 24 0c 8b 44 24 0c <88> 03 e8 71 fc ff ff 85 c0 78 30 e8 b8 fc ff ff 89 c7 41 f7 ec 89
[ 97.489326] RSP: 002b:00007f1d203fded0 EFLAGS: 00010202
[ 97.491336] RAX: 0000000000000001 RBX: 00007f1d20c00000 RCX: 0000000000000000
[ 97.494080] RDX: 0000000000000004 RSI: 0000000000200000 RDI: 00007f1d20c00000
[ 97.497244] RBP: 0000000000000002 R08: 00007f1d2138d230 R09: 00007f1d2138d260
[ 97.500028] R10: 00007f1d203fe9d0 R11: 0000000000000000 R12: 0000000051eb851f
[ 97.502785] R13: 00007fff01d5607f R14: 0000000000000000 R15: 00007f1d203fdfc0
[ 97.505546] ---[ end trace 18f1c94bd7c3d1e1 ]---
Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
---
mm/memory.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 45442d9..e3a1dce 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2269,18 +2269,12 @@ static inline bool cow_user_page(struct page *dst, struct page *src,
/*
* This really shouldn't fail, because the page is there
- * in the page tables. But it might just be unreadable,
- * in which case we just give up and fill the result with
- * zeroes.
+ * in the page tables. But it could happen during races,
+ * or it might just be unreadable, in which cases we
+ * just give up and fill the result with zeroes.
*/
- if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) {
- /*
- * Give a warn in case there can be some obscure
- * use-case
- */
- WARN_ON_ONCE(1);
+ if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
clear_page(kaddr);
- }
ret = true;
--
1.8.3.1
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^ permalink raw reply related [flat|nested] 7+ messages in thread* RE: [PATCH] mm: get rid of WARN if failed to cow user pages 2019-12-25 5:42 [PATCH] mm: get rid of WARN if failed to cow user pages Murphy Zhou @ 2019-12-25 8:17 ` Justin He 2019-12-26 10:53 ` Murphy Zhou 2020-01-15 4:48 ` Murphy Zhou 2020-01-15 6:02 ` Dan Williams 2 siblings, 1 reply; 7+ messages in thread From: Justin He @ 2019-12-25 8:17 UTC (permalink / raw) To: Murphy Zhou, linux-nvdimm, Ross Zwisler Hi Murphy > -----Original Message----- > From: Murphy Zhou <jencce.kernel@gmail.com> > Sent: Wednesday, December 25, 2019 1:42 PM > To: linux-nvdimm@lists.01.org; Justin He <Justin.He@arm.com>; Ross Zwisler > <ross.zwisler@linux.intel.com> > Subject: [PATCH] mm: get rid of WARN if failed to cow user pages > > By running xfstests with fsdax enabled, generic/437 always hits this > warning[1] since this commit: > > commit 83d116c53058d505ddef051e90ab27f57015b025 > Author: Jia He <justin.he@arm.com> > Date: Fri Oct 11 22:09:39 2019 +0800 > > mm: fix double page fault on arm64 if PTE_AF is cleared > > Looking at the test program[2] generic/437 uses, it's pretty easy > to hit this warning. Remove this WARN as it seems not necessary. > > [2] https://git.kernel.org/pub/scm/fs/xfs/xfstests- > dev.git/tree/src/t_mmap_cow_race.c > [1] warning message: > ----------------------------------------------------------------------- > [ 97.344077] WARNING: CPU: 0 PID: 2486 at mm/memory.c:2281 It is hard for me to reproduce it in my x86 desktop when running that generic/437 Could you please share your test env? E.g. guest or host? What is the test_dev of your xfstests? Is it a 100% reproducible issue? Besides, a few days ago, syzbot reported a similar issue, Kirill relied his concerns at [1] [1] https://www.spinics.net/lists/linux-mm/msg199008.html -- Cheers, Justin (Jia He) > wp_page_copy+0x687/0x6e0 > [ 97.348354] Modules linked in: nf_tables nfnetlink rfkill sunrpc > snd_hda_codec_generic ledtrig_audio qxl snd_hda_intel snd_intel_dspcfg > drm_ttm_helper snd_hda_codec ttm snd_hda_core drm_kms_helper > snd_hwdep snd_seq syscopyarea sysfillrect sysimgblt snd_seq_device > fb_sys_fops snd_pcm drm snd_timer crc32_pclmul snd soundcore > dax_pmem_compat i2c_piix4 device_dax virtio_balloon pcspkr joydev > dax_pmem_core ip_tables xfs libcrc32c crct10dif_pclmul crc32c_intel sd_mod > sg ata_generic 8139too ata_piix libata ghash_clmulni_intel 8139cp > virtio_console serio_raw nd_pmem mii dm_mirror dm_region_hash dm_log > dm_mod > [ 97.382176] CPU: 0 PID: 2486 Comm: t_mmap_cow_race Tainted: G W > 5.5.0-rc3-v5.5-rc3 #1 > [ 97.387804] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 > [ 97.392228] RIP: 0010:wp_page_copy+0x687/0x6e0 > [ 97.396572] Code: 95 f5 00 48 81 e6 00 f0 ff ff ba 00 10 00 00 49 c1 ff 06 49 > c1 e7 0c 4c 03 3d 35 95 f5 00 4c 89 ff e8 8d 85 6a 00 85 c0 74 0a <0f> 0b 4c 89 > ff e8 8f 80 6a 00 65 48 8b 04 25 40 7f 01 00 83 a8 d8 > [ 97.413487] RSP: 0000:ffffb882493afd28 EFLAGS: 00010206 > [ 97.417520] RAX: 0000000000001000 RBX: ffffb882493afdf8 RCX: > 0000000000001000 > [ 97.422295] RDX: 0000000000001000 RSI: 00007f1d20c00000 RDI: > ffff976384d1f000 > [ 97.426914] RBP: 0000000000000000 R08: 0000000000000000 R09: > 00000000000ca308 > [ 97.431746] R10: 0000000000000000 R11: ffffe0cd4c1347c0 R12: > ffffe0cd4c1347c0 > [ 97.436371] R13: ffff9763b46ba190 R14: ffff9763a963d0c0 R15: > ffff976384d1f000 > [ 97.441085] FS: 00007f1d203fe700(0000) GS:ffff9763b8a00000(0000) > knlGS:0000000000000000 > [ 97.445500] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 97.448393] CR2: 00007f1d20c00000 CR3: 0000000333dfc000 CR4: > 00000000000006f0 > [ 97.452346] Call Trace: > [ 97.453681] ? __switch_to_asm+0x34/0x70 > [ 97.455566] ? __switch_to_asm+0x40/0x70 > [ 97.457418] ? __switch_to_asm+0x34/0x70 > [ 97.459197] ? __switch_to_asm+0x40/0x70 > [ 97.460971] ? __switch_to_asm+0x34/0x70 > [ 97.462746] ? __switch_to_asm+0x40/0x70 > [ 97.464561] ? __switch_to_asm+0x34/0x70 > [ 97.466342] ? __switch_to_asm+0x40/0x70 > [ 97.468141] do_wp_page+0x8c/0x640 > [ 97.469818] ? finish_task_switch+0x77/0x2a0 > [ 97.471631] __handle_mm_fault+0xa06/0x1420 > [ 97.473517] handle_mm_fault+0xae/0x1d0 > [ 97.475168] __do_page_fault+0x27f/0x4e0 > [ 97.476947] do_page_fault+0x30/0x110 > [ 97.478490] async_page_fault+0x39/0x40 > [ 97.480275] RIP: 0033:0x400d68 > [ 97.481587] Code: 53 48 89 fb 48 83 ec 10 66 2e 0f 1f 84 00 00 00 00 00 0f > b6 03 ba 04 00 00 00 be 00 00 20 00 48 89 df 89 44 24 0c 8b 44 24 0c <88> 03 > e8 71 fc ff ff 85 c0 78 30 e8 b8 fc ff ff 89 c7 41 f7 ec 89 > [ 97.489326] RSP: 002b:00007f1d203fded0 EFLAGS: 00010202 > [ 97.491336] RAX: 0000000000000001 RBX: 00007f1d20c00000 RCX: > 0000000000000000 > [ 97.494080] RDX: 0000000000000004 RSI: 0000000000200000 RDI: > 00007f1d20c00000 > [ 97.497244] RBP: 0000000000000002 R08: 00007f1d2138d230 R09: > 00007f1d2138d260 > [ 97.500028] R10: 00007f1d203fe9d0 R11: 0000000000000000 R12: > 0000000051eb851f > [ 97.502785] R13: 00007fff01d5607f R14: 0000000000000000 R15: > 00007f1d203fdfc0 > [ 97.505546] ---[ end trace 18f1c94bd7c3d1e1 ]--- > > Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com> > --- > mm/memory.c | 14 ++++---------- > 1 file changed, 4 insertions(+), 10 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index 45442d9..e3a1dce 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2269,18 +2269,12 @@ static inline bool cow_user_page(struct page > *dst, struct page *src, > > /* > * This really shouldn't fail, because the page is there > - * in the page tables. But it might just be unreadable, > - * in which case we just give up and fill the result with > - * zeroes. > + * in the page tables. But it could happen during races, > + * or it might just be unreadable, in which cases we > + * just give up and fill the result with zeroes. > */ > - if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { > - /* > - * Give a warn in case there can be some obscure > - * use-case > - */ > - WARN_ON_ONCE(1); > + if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) > clear_page(kaddr); > - } > > ret = true; > > -- > 1.8.3.1 IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] mm: get rid of WARN if failed to cow user pages 2019-12-25 8:17 ` Justin He @ 2019-12-26 10:53 ` Murphy Zhou 0 siblings, 0 replies; 7+ messages in thread From: Murphy Zhou @ 2019-12-26 10:53 UTC (permalink / raw) To: Justin He; +Cc: linux-nvdimm On Wed, Dec 25, 2019 at 08:17:29AM +0000, Justin He wrote: > Hi Murphy > > > -----Original Message----- > > From: Murphy Zhou <jencce.kernel@gmail.com> > > Sent: Wednesday, December 25, 2019 1:42 PM > > To: linux-nvdimm@lists.01.org; Justin He <Justin.He@arm.com>; Ross Zwisler > > <ross.zwisler@linux.intel.com> > > Subject: [PATCH] mm: get rid of WARN if failed to cow user pages > > > > By running xfstests with fsdax enabled, generic/437 always hits this > > warning[1] since this commit: > > > > commit 83d116c53058d505ddef051e90ab27f57015b025 > > Author: Jia He <justin.he@arm.com> > > Date: Fri Oct 11 22:09:39 2019 +0800 > > > > mm: fix double page fault on arm64 if PTE_AF is cleared > > > > Looking at the test program[2] generic/437 uses, it's pretty easy > > to hit this warning. Remove this WARN as it seems not necessary. > > > > [2] https://git.kernel.org/pub/scm/fs/xfs/xfstests- > > dev.git/tree/src/t_mmap_cow_race.c > > [1] warning message: > > ----------------------------------------------------------------------- > > [ 97.344077] WARNING: CPU: 0 PID: 2486 at mm/memory.c:2281 > It is hard for me to reproduce it in my x86 desktop when running that generic/437 > > Could you please share your test env? E.g. guest or host? What is the test_dev of > your xfstests? Is it a 100% reproducible issue? It's a kvm guest, with pmem ramdisks. 100% reproducible. [root@8u ~]# uname -r 5.5.0-rc3-v5.5-rc3 [root@8u ~]# cat /proc/cmdline BOOT_IMAGE=(hd0,msdos2)/boot/vmlinuz-5.5.0-rc3-v5.5-rc3 root=UUID=62b76d7e-e314-4400-9ea7-ded0de2f9fca ro crashkernel=auto resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/swap console=ttyS0,115200 memmap=5G!6G memmap=5G!13G [root@8u ~]# lspci 00:00.0 Host bridge: Intel Corporation 440FX - 82441FX PMC [Natoma] (rev 02) 00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II] 00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II] 00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03) 00:02.0 VGA compatible controller: Red Hat, Inc. QXL paravirtual graphic card (rev 04) 00:03.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8100/8101L/8139 PCI Fast Ethernet Adapter (rev 20) 00:04.0 Audio device: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) High Definition Audio Controller (rev 01) 00:05.0 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 03) 00:05.1 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 03) 00:05.2 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 03) 00:05.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 03) 00:06.0 Communication controller: Red Hat, Inc. Virtio console 00:07.0 Unclassified device [00ff]: Red Hat, Inc. Virtio memory balloon 00:08.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8100/8101L/8139 PCI Fast Ethernet Adapter (rev 20) [root@8u ~]# [root@8u ~]# ndctl list [ { "dev":"namespace0.0", "mode":"fsdax", "map":"mem", "size":5368709120, "sector_size":512, "blockdev":"pmem0" } ] [root@8u ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 620G 0 disk ├─sda1 8:1 0 2G 0 part │ └─rhel-swap 253:0 0 2G 0 lvm [SWAP] └─sda2 8:2 0 618G 0 part / sdb 8:16 0 200G 0 disk /home sdc 8:32 0 20G 0 disk ├─sdc1 8:33 0 10G 0 part └─sdc2 8:34 0 10G 0 part pmem0 259:0 0 5G 0 disk ├─pmem0p1 259:1 0 2.4G 0 part └─pmem0p2 259:2 0 2.6G 0 part [root@8u ~]# [root@8u xfstests-dev (master)]# cat local.config TEST_DEV=/dev/pmem0p1 TEST_DIR=/test2 SCRATCH_DEV=/dev/pmem0p2 SCRATCH_MNT=/test1 FSTYP=xfs MOUNT_OPTIONS="-o dax" TEST_FS_MOUNT_OPTS="-o dax" MKFS_OPTIONS="-f -b size=4096 -m reflink=0" LOGWRITES_DEV="" [root@8u xfstests-dev (master)]# > > Besides, a few days ago, syzbot reported a similar issue, Kirill relied his concerns > at [1] > > [1] https://www.spinics.net/lists/linux-mm/msg199008.html > > -- > Cheers, > Justin (Jia He) > > > > wp_page_copy+0x687/0x6e0 > > [ 97.348354] Modules linked in: nf_tables nfnetlink rfkill sunrpc > > snd_hda_codec_generic ledtrig_audio qxl snd_hda_intel snd_intel_dspcfg > > drm_ttm_helper snd_hda_codec ttm snd_hda_core drm_kms_helper > > snd_hwdep snd_seq syscopyarea sysfillrect sysimgblt snd_seq_device > > fb_sys_fops snd_pcm drm snd_timer crc32_pclmul snd soundcore > > dax_pmem_compat i2c_piix4 device_dax virtio_balloon pcspkr joydev > > dax_pmem_core ip_tables xfs libcrc32c crct10dif_pclmul crc32c_intel sd_mod > > sg ata_generic 8139too ata_piix libata ghash_clmulni_intel 8139cp > > virtio_console serio_raw nd_pmem mii dm_mirror dm_region_hash dm_log > > dm_mod > > [ 97.382176] CPU: 0 PID: 2486 Comm: t_mmap_cow_race Tainted: G W > > 5.5.0-rc3-v5.5-rc3 #1 > > [ 97.387804] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 > > [ 97.392228] RIP: 0010:wp_page_copy+0x687/0x6e0 > > [ 97.396572] Code: 95 f5 00 48 81 e6 00 f0 ff ff ba 00 10 00 00 49 c1 ff 06 49 > > c1 e7 0c 4c 03 3d 35 95 f5 00 4c 89 ff e8 8d 85 6a 00 85 c0 74 0a <0f> 0b 4c 89 > > ff e8 8f 80 6a 00 65 48 8b 04 25 40 7f 01 00 83 a8 d8 > > [ 97.413487] RSP: 0000:ffffb882493afd28 EFLAGS: 00010206 > > [ 97.417520] RAX: 0000000000001000 RBX: ffffb882493afdf8 RCX: > > 0000000000001000 > > [ 97.422295] RDX: 0000000000001000 RSI: 00007f1d20c00000 RDI: > > ffff976384d1f000 > > [ 97.426914] RBP: 0000000000000000 R08: 0000000000000000 R09: > > 00000000000ca308 > > [ 97.431746] R10: 0000000000000000 R11: ffffe0cd4c1347c0 R12: > > ffffe0cd4c1347c0 > > [ 97.436371] R13: ffff9763b46ba190 R14: ffff9763a963d0c0 R15: > > ffff976384d1f000 > > [ 97.441085] FS: 00007f1d203fe700(0000) GS:ffff9763b8a00000(0000) > > knlGS:0000000000000000 > > [ 97.445500] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 97.448393] CR2: 00007f1d20c00000 CR3: 0000000333dfc000 CR4: > > 00000000000006f0 > > [ 97.452346] Call Trace: > > [ 97.453681] ? __switch_to_asm+0x34/0x70 > > [ 97.455566] ? __switch_to_asm+0x40/0x70 > > [ 97.457418] ? __switch_to_asm+0x34/0x70 > > [ 97.459197] ? __switch_to_asm+0x40/0x70 > > [ 97.460971] ? __switch_to_asm+0x34/0x70 > > [ 97.462746] ? __switch_to_asm+0x40/0x70 > > [ 97.464561] ? __switch_to_asm+0x34/0x70 > > [ 97.466342] ? __switch_to_asm+0x40/0x70 > > [ 97.468141] do_wp_page+0x8c/0x640 > > [ 97.469818] ? finish_task_switch+0x77/0x2a0 > > [ 97.471631] __handle_mm_fault+0xa06/0x1420 > > [ 97.473517] handle_mm_fault+0xae/0x1d0 > > [ 97.475168] __do_page_fault+0x27f/0x4e0 > > [ 97.476947] do_page_fault+0x30/0x110 > > [ 97.478490] async_page_fault+0x39/0x40 > > [ 97.480275] RIP: 0033:0x400d68 > > [ 97.481587] Code: 53 48 89 fb 48 83 ec 10 66 2e 0f 1f 84 00 00 00 00 00 0f > > b6 03 ba 04 00 00 00 be 00 00 20 00 48 89 df 89 44 24 0c 8b 44 24 0c <88> 03 > > e8 71 fc ff ff 85 c0 78 30 e8 b8 fc ff ff 89 c7 41 f7 ec 89 > > [ 97.489326] RSP: 002b:00007f1d203fded0 EFLAGS: 00010202 > > [ 97.491336] RAX: 0000000000000001 RBX: 00007f1d20c00000 RCX: > > 0000000000000000 > > [ 97.494080] RDX: 0000000000000004 RSI: 0000000000200000 RDI: > > 00007f1d20c00000 > > [ 97.497244] RBP: 0000000000000002 R08: 00007f1d2138d230 R09: > > 00007f1d2138d260 > > [ 97.500028] R10: 00007f1d203fe9d0 R11: 0000000000000000 R12: > > 0000000051eb851f > > [ 97.502785] R13: 00007fff01d5607f R14: 0000000000000000 R15: > > 00007f1d203fdfc0 > > [ 97.505546] ---[ end trace 18f1c94bd7c3d1e1 ]--- > > > > Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com> > > --- > > mm/memory.c | 14 ++++---------- > > 1 file changed, 4 insertions(+), 10 deletions(-) > > > > diff --git a/mm/memory.c b/mm/memory.c > > index 45442d9..e3a1dce 100644 > > --- a/mm/memory.c > > +++ b/mm/memory.c > > @@ -2269,18 +2269,12 @@ static inline bool cow_user_page(struct page > > *dst, struct page *src, > > > > /* > > * This really shouldn't fail, because the page is there > > - * in the page tables. But it might just be unreadable, > > - * in which case we just give up and fill the result with > > - * zeroes. > > + * in the page tables. But it could happen during races, > > + * or it might just be unreadable, in which cases we > > + * just give up and fill the result with zeroes. > > */ > > - if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { > > - /* > > - * Give a warn in case there can be some obscure > > - * use-case > > - */ > > - WARN_ON_ONCE(1); > > + if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) > > clear_page(kaddr); > > - } > > > > ret = true; > > > > -- > > 1.8.3.1 > > IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] mm: get rid of WARN if failed to cow user pages 2019-12-25 5:42 [PATCH] mm: get rid of WARN if failed to cow user pages Murphy Zhou 2019-12-25 8:17 ` Justin He @ 2020-01-15 4:48 ` Murphy Zhou 2020-01-15 6:02 ` Dan Williams 2 siblings, 0 replies; 7+ messages in thread From: Murphy Zhou @ 2020-01-15 4:48 UTC (permalink / raw) To: linux-nvdimm, Jia He, Ross Zwisler Ping ? On Wed, Dec 25, 2019 at 01:42:27PM +0800, Murphy Zhou wrote: > By running xfstests with fsdax enabled, generic/437 always hits this > warning[1] since this commit: > > commit 83d116c53058d505ddef051e90ab27f57015b025 > Author: Jia He <justin.he@arm.com> > Date: Fri Oct 11 22:09:39 2019 +0800 > > mm: fix double page fault on arm64 if PTE_AF is cleared > > Looking at the test program[2] generic/437 uses, it's pretty easy > to hit this warning. Remove this WARN as it seems not necessary. > > [2] https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/tree/src/t_mmap_cow_race.c > [1] warning message: > ----------------------------------------------------------------------- > [ 97.344077] WARNING: CPU: 0 PID: 2486 at mm/memory.c:2281 wp_page_copy+0x687/0x6e0 > [ 97.348354] Modules linked in: nf_tables nfnetlink rfkill sunrpc snd_hda_codec_generic ledtrig_audio qxl snd_hda_intel snd_intel_dspcfg drm_ttm_helper snd_hda_codec ttm snd_hda_core drm_kms_helper snd_hwdep snd_seq syscopyarea sysfillrect sysimgblt snd_seq_device fb_sys_fops snd_pcm drm snd_timer crc32_pclmul snd soundcore dax_pmem_compat i2c_piix4 device_dax virtio_balloon pcspkr joydev dax_pmem_core ip_tables xfs libcrc32c crct10dif_pclmul crc32c_intel sd_mod sg ata_generic 8139too ata_piix libata ghash_clmulni_intel 8139cp virtio_console serio_raw nd_pmem mii dm_mirror dm_region_hash dm_log dm_mod > [ 97.382176] CPU: 0 PID: 2486 Comm: t_mmap_cow_race Tainted: G W 5.5.0-rc3-v5.5-rc3 #1 > [ 97.387804] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 > [ 97.392228] RIP: 0010:wp_page_copy+0x687/0x6e0 > [ 97.396572] Code: 95 f5 00 48 81 e6 00 f0 ff ff ba 00 10 00 00 49 c1 ff 06 49 c1 e7 0c 4c 03 3d 35 95 f5 00 4c 89 ff e8 8d 85 6a 00 85 c0 74 0a <0f> 0b 4c 89 ff e8 8f 80 6a 00 65 48 8b 04 25 40 7f 01 00 83 a8 d8 > [ 97.413487] RSP: 0000:ffffb882493afd28 EFLAGS: 00010206 > [ 97.417520] RAX: 0000000000001000 RBX: ffffb882493afdf8 RCX: 0000000000001000 > [ 97.422295] RDX: 0000000000001000 RSI: 00007f1d20c00000 RDI: ffff976384d1f000 > [ 97.426914] RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000ca308 > [ 97.431746] R10: 0000000000000000 R11: ffffe0cd4c1347c0 R12: ffffe0cd4c1347c0 > [ 97.436371] R13: ffff9763b46ba190 R14: ffff9763a963d0c0 R15: ffff976384d1f000 > [ 97.441085] FS: 00007f1d203fe700(0000) GS:ffff9763b8a00000(0000) knlGS:0000000000000000 > [ 97.445500] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 97.448393] CR2: 00007f1d20c00000 CR3: 0000000333dfc000 CR4: 00000000000006f0 > [ 97.452346] Call Trace: > [ 97.453681] ? __switch_to_asm+0x34/0x70 > [ 97.455566] ? __switch_to_asm+0x40/0x70 > [ 97.457418] ? __switch_to_asm+0x34/0x70 > [ 97.459197] ? __switch_to_asm+0x40/0x70 > [ 97.460971] ? __switch_to_asm+0x34/0x70 > [ 97.462746] ? __switch_to_asm+0x40/0x70 > [ 97.464561] ? __switch_to_asm+0x34/0x70 > [ 97.466342] ? __switch_to_asm+0x40/0x70 > [ 97.468141] do_wp_page+0x8c/0x640 > [ 97.469818] ? finish_task_switch+0x77/0x2a0 > [ 97.471631] __handle_mm_fault+0xa06/0x1420 > [ 97.473517] handle_mm_fault+0xae/0x1d0 > [ 97.475168] __do_page_fault+0x27f/0x4e0 > [ 97.476947] do_page_fault+0x30/0x110 > [ 97.478490] async_page_fault+0x39/0x40 > [ 97.480275] RIP: 0033:0x400d68 > [ 97.481587] Code: 53 48 89 fb 48 83 ec 10 66 2e 0f 1f 84 00 00 00 00 00 0f b6 03 ba 04 00 00 00 be 00 00 20 00 48 89 df 89 44 24 0c 8b 44 24 0c <88> 03 e8 71 fc ff ff 85 c0 78 30 e8 b8 fc ff ff 89 c7 41 f7 ec 89 > [ 97.489326] RSP: 002b:00007f1d203fded0 EFLAGS: 00010202 > [ 97.491336] RAX: 0000000000000001 RBX: 00007f1d20c00000 RCX: 0000000000000000 > [ 97.494080] RDX: 0000000000000004 RSI: 0000000000200000 RDI: 00007f1d20c00000 > [ 97.497244] RBP: 0000000000000002 R08: 00007f1d2138d230 R09: 00007f1d2138d260 > [ 97.500028] R10: 00007f1d203fe9d0 R11: 0000000000000000 R12: 0000000051eb851f > [ 97.502785] R13: 00007fff01d5607f R14: 0000000000000000 R15: 00007f1d203fdfc0 > [ 97.505546] ---[ end trace 18f1c94bd7c3d1e1 ]--- > > Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com> > --- > mm/memory.c | 14 ++++---------- > 1 file changed, 4 insertions(+), 10 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index 45442d9..e3a1dce 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2269,18 +2269,12 @@ static inline bool cow_user_page(struct page *dst, struct page *src, > > /* > * This really shouldn't fail, because the page is there > - * in the page tables. But it might just be unreadable, > - * in which case we just give up and fill the result with > - * zeroes. > + * in the page tables. But it could happen during races, > + * or it might just be unreadable, in which cases we > + * just give up and fill the result with zeroes. > */ > - if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) { > - /* > - * Give a warn in case there can be some obscure > - * use-case > - */ > - WARN_ON_ONCE(1); > + if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) > clear_page(kaddr); > - } > > ret = true; > > -- > 1.8.3.1 > _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] mm: get rid of WARN if failed to cow user pages 2019-12-25 5:42 [PATCH] mm: get rid of WARN if failed to cow user pages Murphy Zhou 2019-12-25 8:17 ` Justin He 2020-01-15 4:48 ` Murphy Zhou @ 2020-01-15 6:02 ` Dan Williams 2020-02-18 21:09 ` Jeff Moyer 2 siblings, 1 reply; 7+ messages in thread From: Dan Williams @ 2020-01-15 6:02 UTC (permalink / raw) To: Murphy Zhou Cc: linux-nvdimm, Jia He, Linux MM, Shutemov, Kirill, Linux Kernel Mailing List [ drop Ross, add Kirill, linux-mm, and lkml ] On Tue, Dec 24, 2019 at 9:42 PM Murphy Zhou <jencce.kernel@gmail.com> wrote: > > By running xfstests with fsdax enabled, generic/437 always hits this > warning[1] since this commit: > > commit 83d116c53058d505ddef051e90ab27f57015b025 > Author: Jia He <justin.he@arm.com> > Date: Fri Oct 11 22:09:39 2019 +0800 > > mm: fix double page fault on arm64 if PTE_AF is cleared > > Looking at the test program[2] generic/437 uses, it's pretty easy > to hit this warning. Remove this WARN as it seems not necessary. This is not sufficient justification. Does this same test fail without DAX? If not, why not? At a minimum you need to explain why this is not indicating a problem. _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] mm: get rid of WARN if failed to cow user pages 2020-01-15 6:02 ` Dan Williams @ 2020-02-18 21:09 ` Jeff Moyer 2020-02-19 1:58 ` Murphy Zhou 0 siblings, 1 reply; 7+ messages in thread From: Jeff Moyer @ 2020-02-18 21:09 UTC (permalink / raw) To: Dan Williams Cc: linux-nvdimm, Jia He, Linux MM, Shutemov, Kirill, Linux Kernel Mailing List Dan Williams <dan.j.williams@intel.com> writes: > [ drop Ross, add Kirill, linux-mm, and lkml ] > > On Tue, Dec 24, 2019 at 9:42 PM Murphy Zhou <jencce.kernel@gmail.com> wrote: >> >> By running xfstests with fsdax enabled, generic/437 always hits this >> warning[1] since this commit: >> >> commit 83d116c53058d505ddef051e90ab27f57015b025 >> Author: Jia He <justin.he@arm.com> >> Date: Fri Oct 11 22:09:39 2019 +0800 >> >> mm: fix double page fault on arm64 if PTE_AF is cleared >> >> Looking at the test program[2] generic/437 uses, it's pretty easy >> to hit this warning. Remove this WARN as it seems not necessary. > > This is not sufficient justification. Does this same test fail without > DAX? If not, why not? At a minimum you need to explain why this is not > indicating a problem. I ran into this, too, and Kirill has posted a patch[1] to fix the issue. Note that it's a potential data corrupter, so just removing the warning is NOT the right approach. :) -Jeff [1] https://lore.kernel.org/linux-mm/20200218154151.13349-1-kirill.shutemov@linux.intel.com/T/#u _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] mm: get rid of WARN if failed to cow user pages 2020-02-18 21:09 ` Jeff Moyer @ 2020-02-19 1:58 ` Murphy Zhou 0 siblings, 0 replies; 7+ messages in thread From: Murphy Zhou @ 2020-02-19 1:58 UTC (permalink / raw) To: Jeff Moyer Cc: linux-nvdimm, Jia He, Linux MM, Shutemov, Kirill, Linux Kernel Mailing List On Tue, Feb 18, 2020 at 04:09:30PM -0500, Jeff Moyer wrote: > Dan Williams <dan.j.williams@intel.com> writes: > > > [ drop Ross, add Kirill, linux-mm, and lkml ] > > > > On Tue, Dec 24, 2019 at 9:42 PM Murphy Zhou <jencce.kernel@gmail.com> wrote: > >> > >> By running xfstests with fsdax enabled, generic/437 always hits this > >> warning[1] since this commit: > >> > >> commit 83d116c53058d505ddef051e90ab27f57015b025 > >> Author: Jia He <justin.he@arm.com> > >> Date: Fri Oct 11 22:09:39 2019 +0800 > >> > >> mm: fix double page fault on arm64 if PTE_AF is cleared > >> > >> Looking at the test program[2] generic/437 uses, it's pretty easy > >> to hit this warning. Remove this WARN as it seems not necessary. > > > > This is not sufficient justification. Does this same test fail without > > DAX? If not, why not? At a minimum you need to explain why this is not > > indicating a problem. > > I ran into this, too, and Kirill has posted a patch[1] to fix the issue. > Note that it's a potential data corrupter, so just removing the warning > is NOT the right approach. :) Agree :) Thanks! > > -Jeff > > [1] https://lore.kernel.org/linux-mm/20200218154151.13349-1-kirill.shutemov@linux.intel.com/T/#u > _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-02-19 1:58 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-12-25 5:42 [PATCH] mm: get rid of WARN if failed to cow user pages Murphy Zhou 2019-12-25 8:17 ` Justin He 2019-12-26 10:53 ` Murphy Zhou 2020-01-15 4:48 ` Murphy Zhou 2020-01-15 6:02 ` Dan Williams 2020-02-18 21:09 ` Jeff Moyer 2020-02-19 1:58 ` Murphy Zhou
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