2017-04-28 09:56:31

by Corentin Labbe

[permalink] [raw]
Subject: [BUG] cannot mount nfs, bisected to 0db10944a76ba ("nfs: Convert to separately allocated bdi")

Hello

Since linux next-20170421, mounting nfs give me:
[ 774.994934] ------------[ cut here ]------------
[ 774.994975] WARNING: CPU: 1 PID: 10284 at /linux-next/fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x74
[ 774.994985] sysfs: cannot create duplicate filename '/devices/virtual/bdi/0:32'
[ 774.994992] Modules linked in: axp20x_usb_power gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
[ 774.995047] CPU: 1 PID: 10284 Comm: mount.nfs Not tainted 4.11.0-rc4+ #14
[ 774.995054] Hardware name: Allwinner sun7i (A20) Family
[ 774.995085] [<c010f19c>] (unwind_backtrace) from [<c010bc74>] (show_stack+0x10/0x14)
[ 774.995104] [<c010bc74>] (show_stack) from [<c03c6e24>] (dump_stack+0x78/0x8c)
[ 774.995121] [<c03c6e24>] (dump_stack) from [<c0122200>] (__warn+0xe8/0x100)
[ 774.995135] [<c0122200>] (__warn) from [<c0122250>] (warn_slowpath_fmt+0x38/0x48)
[ 774.995150] [<c0122250>] (warn_slowpath_fmt) from [<c02ac178>] (sysfs_warn_dup+0x64/0x74)
[ 774.995167] [<c02ac178>] (sysfs_warn_dup) from [<c02ac254>] (sysfs_create_dir_ns+0x84/0x94)
[ 774.995184] [<c02ac254>] (sysfs_create_dir_ns) from [<c03c8b8c>] (kobject_add_internal+0x9c/0x2ec)
[ 774.995199] [<c03c8b8c>] (kobject_add_internal) from [<c03c8e24>] (kobject_add+0x48/0x98)
[ 774.995217] [<c03c8e24>] (kobject_add) from [<c048d75c>] (device_add+0xe4/0x5a0)
[ 774.995232] [<c048d75c>] (device_add) from [<c048ddb4>] (device_create_groups_vargs+0xac/0xbc)
[ 774.995247] [<c048ddb4>] (device_create_groups_vargs) from [<c048dde4>] (device_create_vargs+0x20/0x28)
[ 774.995263] [<c048dde4>] (device_create_vargs) from [<c02075c8>] (bdi_register_va+0x44/0xfc)
[ 774.995280] [<c02075c8>] (bdi_register_va) from [<c023d378>] (super_setup_bdi_name+0x48/0xa4)
[ 774.995299] [<c023d378>] (super_setup_bdi_name) from [<c0312ef4>] (nfs_fill_super+0x1a4/0x204)
[ 774.995315] [<c0312ef4>] (nfs_fill_super) from [<c03133f0>] (nfs_fs_mount_common+0x140/0x1e8)
[ 774.995333] [<c03133f0>] (nfs_fs_mount_common) from [<c03335cc>] (nfs4_remote_mount+0x50/0x58)
[ 774.995349] [<c03335cc>] (nfs4_remote_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
[ 774.995368] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
[ 774.995385] [<c025cba0>] (vfs_kern_mount) from [<c033352c>] (nfs_do_root_mount+0x80/0xa0)
[ 774.995400] [<c033352c>] (nfs_do_root_mount) from [<c0333818>] (nfs4_try_mount+0x28/0x3c)
[ 774.995415] [<c0333818>] (nfs4_try_mount) from [<c0313874>] (nfs_fs_mount+0x2cc/0x8c4)
[ 774.995430] [<c0313874>] (nfs_fs_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
[ 774.995445] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
[ 774.995461] [<c025cba0>] (vfs_kern_mount) from [<c02600f0>] (do_mount+0x158/0xc7c)
[ 774.995475] [<c02600f0>] (do_mount) from [<c0260f98>] (SyS_mount+0x8c/0xb4)
[ 774.995491] [<c0260f98>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 774.995501] ---[ end trace 0665e451f8864ff0 ]---
[ 774.995512] ------------[ cut here ]------------
[ 774.995526] WARNING: CPU: 1 PID: 10284 at /linux-next/lib/kobject.c:240 kobject_add_internal+0x274/0x2ec
[ 774.995535] kobject_add_internal failed for 0:32 with -EEXIST, don't try to register things with the same name in the same directory.
[ 774.995541] Modules linked in: axp20x_usb_power gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
[ 774.995590] CPU: 1 PID: 10284 Comm: mount.nfs Tainted: G W 4.11.0-rc4+ #14
[ 774.995597] Hardware name: Allwinner sun7i (A20) Family
[ 774.995612] [<c010f19c>] (unwind_backtrace) from [<c010bc74>] (show_stack+0x10/0x14)
[ 774.995626] [<c010bc74>] (show_stack) from [<c03c6e24>] (dump_stack+0x78/0x8c)
[ 774.995640] [<c03c6e24>] (dump_stack) from [<c0122200>] (__warn+0xe8/0x100)
[ 774.995653] [<c0122200>] (__warn) from [<c0122250>] (warn_slowpath_fmt+0x38/0x48)
[ 774.995668] [<c0122250>] (warn_slowpath_fmt) from [<c03c8d64>] (kobject_add_internal+0x274/0x2ec)
[ 774.995683] [<c03c8d64>] (kobject_add_internal) from [<c03c8e24>] (kobject_add+0x48/0x98)
[ 774.995698] [<c03c8e24>] (kobject_add) from [<c048d75c>] (device_add+0xe4/0x5a0)
[ 774.995712] [<c048d75c>] (device_add) from [<c048ddb4>] (device_create_groups_vargs+0xac/0xbc)
[ 774.995727] [<c048ddb4>] (device_create_groups_vargs) from [<c048dde4>] (device_create_vargs+0x20/0x28)
[ 774.995740] [<c048dde4>] (device_create_vargs) from [<c02075c8>] (bdi_register_va+0x44/0xfc)
[ 774.995755] [<c02075c8>] (bdi_register_va) from [<c023d378>] (super_setup_bdi_name+0x48/0xa4)
[ 774.995771] [<c023d378>] (super_setup_bdi_name) from [<c0312ef4>] (nfs_fill_super+0x1a4/0x204)
[ 774.995785] [<c0312ef4>] (nfs_fill_super) from [<c03133f0>] (nfs_fs_mount_common+0x140/0x1e8)
[ 774.995800] [<c03133f0>] (nfs_fs_mount_common) from [<c03335cc>] (nfs4_remote_mount+0x50/0x58)
[ 774.995816] [<c03335cc>] (nfs4_remote_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
[ 774.995831] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
[ 774.995847] [<c025cba0>] (vfs_kern_mount) from [<c033352c>] (nfs_do_root_mount+0x80/0xa0)
[ 774.995862] [<c033352c>] (nfs_do_root_mount) from [<c0333818>] (nfs4_try_mount+0x28/0x3c)
[ 774.995877] [<c0333818>] (nfs4_try_mount) from [<c0313874>] (nfs_fs_mount+0x2cc/0x8c4)
[ 774.995891] [<c0313874>] (nfs_fs_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
[ 774.995907] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
[ 774.995921] [<c025cba0>] (vfs_kern_mount) from [<c02600f0>] (do_mount+0x158/0xc7c)
[ 774.995935] [<c02600f0>] (do_mount) from [<c0260f98>] (SyS_mount+0x8c/0xb4)
[ 774.995949] [<c0260f98>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 774.995958] ---[ end trace 0665e451f8864ff1 ]---

The mount command is
mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/local_kernel /usr/src/

the mount command failling with: "mount.nfs: Cannot allocate memory"

Regards


2017-04-28 10:09:24

by Jan Kara

[permalink] [raw]
Subject: Re: [BUG] cannot mount nfs, bisected to 0db10944a76ba ("nfs: Convert to separately allocated bdi")

Hello,

thanks for report. I'm heading out now but I'll have a look next week. From
a quick look it seems like some problem with uniqueness of bdi names as
generated by NFS bdi.

Honza

On Fri 28-04-17 11:56:24, Corentin Labbe wrote:
> Since linux next-20170421, mounting nfs give me:
> [ 774.994934] ------------[ cut here ]------------
> [ 774.994975] WARNING: CPU: 1 PID: 10284 at /linux-next/fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x74
> [ 774.994985] sysfs: cannot create duplicate filename '/devices/virtual/bdi/0:32'
> [ 774.994992] Modules linked in: axp20x_usb_power gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
> [ 774.995047] CPU: 1 PID: 10284 Comm: mount.nfs Not tainted 4.11.0-rc4+ #14
> [ 774.995054] Hardware name: Allwinner sun7i (A20) Family
> [ 774.995085] [<c010f19c>] (unwind_backtrace) from [<c010bc74>] (show_stack+0x10/0x14)
> [ 774.995104] [<c010bc74>] (show_stack) from [<c03c6e24>] (dump_stack+0x78/0x8c)
> [ 774.995121] [<c03c6e24>] (dump_stack) from [<c0122200>] (__warn+0xe8/0x100)
> [ 774.995135] [<c0122200>] (__warn) from [<c0122250>] (warn_slowpath_fmt+0x38/0x48)
> [ 774.995150] [<c0122250>] (warn_slowpath_fmt) from [<c02ac178>] (sysfs_warn_dup+0x64/0x74)
> [ 774.995167] [<c02ac178>] (sysfs_warn_dup) from [<c02ac254>] (sysfs_create_dir_ns+0x84/0x94)
> [ 774.995184] [<c02ac254>] (sysfs_create_dir_ns) from [<c03c8b8c>] (kobject_add_internal+0x9c/0x2ec)
> [ 774.995199] [<c03c8b8c>] (kobject_add_internal) from [<c03c8e24>] (kobject_add+0x48/0x98)
> [ 774.995217] [<c03c8e24>] (kobject_add) from [<c048d75c>] (device_add+0xe4/0x5a0)
> [ 774.995232] [<c048d75c>] (device_add) from [<c048ddb4>] (device_create_groups_vargs+0xac/0xbc)
> [ 774.995247] [<c048ddb4>] (device_create_groups_vargs) from [<c048dde4>] (device_create_vargs+0x20/0x28)
> [ 774.995263] [<c048dde4>] (device_create_vargs) from [<c02075c8>] (bdi_register_va+0x44/0xfc)
> [ 774.995280] [<c02075c8>] (bdi_register_va) from [<c023d378>] (super_setup_bdi_name+0x48/0xa4)
> [ 774.995299] [<c023d378>] (super_setup_bdi_name) from [<c0312ef4>] (nfs_fill_super+0x1a4/0x204)
> [ 774.995315] [<c0312ef4>] (nfs_fill_super) from [<c03133f0>] (nfs_fs_mount_common+0x140/0x1e8)
> [ 774.995333] [<c03133f0>] (nfs_fs_mount_common) from [<c03335cc>] (nfs4_remote_mount+0x50/0x58)
> [ 774.995349] [<c03335cc>] (nfs4_remote_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> [ 774.995368] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> [ 774.995385] [<c025cba0>] (vfs_kern_mount) from [<c033352c>] (nfs_do_root_mount+0x80/0xa0)
> [ 774.995400] [<c033352c>] (nfs_do_root_mount) from [<c0333818>] (nfs4_try_mount+0x28/0x3c)
> [ 774.995415] [<c0333818>] (nfs4_try_mount) from [<c0313874>] (nfs_fs_mount+0x2cc/0x8c4)
> [ 774.995430] [<c0313874>] (nfs_fs_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> [ 774.995445] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> [ 774.995461] [<c025cba0>] (vfs_kern_mount) from [<c02600f0>] (do_mount+0x158/0xc7c)
> [ 774.995475] [<c02600f0>] (do_mount) from [<c0260f98>] (SyS_mount+0x8c/0xb4)
> [ 774.995491] [<c0260f98>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
> [ 774.995501] ---[ end trace 0665e451f8864ff0 ]---
> [ 774.995512] ------------[ cut here ]------------
> [ 774.995526] WARNING: CPU: 1 PID: 10284 at /linux-next/lib/kobject.c:240 kobject_add_internal+0x274/0x2ec
> [ 774.995535] kobject_add_internal failed for 0:32 with -EEXIST, don't try to register things with the same name in the same directory.
> [ 774.995541] Modules linked in: axp20x_usb_power gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
> [ 774.995590] CPU: 1 PID: 10284 Comm: mount.nfs Tainted: G W 4.11.0-rc4+ #14
> [ 774.995597] Hardware name: Allwinner sun7i (A20) Family
> [ 774.995612] [<c010f19c>] (unwind_backtrace) from [<c010bc74>] (show_stack+0x10/0x14)
> [ 774.995626] [<c010bc74>] (show_stack) from [<c03c6e24>] (dump_stack+0x78/0x8c)
> [ 774.995640] [<c03c6e24>] (dump_stack) from [<c0122200>] (__warn+0xe8/0x100)
> [ 774.995653] [<c0122200>] (__warn) from [<c0122250>] (warn_slowpath_fmt+0x38/0x48)
> [ 774.995668] [<c0122250>] (warn_slowpath_fmt) from [<c03c8d64>] (kobject_add_internal+0x274/0x2ec)
> [ 774.995683] [<c03c8d64>] (kobject_add_internal) from [<c03c8e24>] (kobject_add+0x48/0x98)
> [ 774.995698] [<c03c8e24>] (kobject_add) from [<c048d75c>] (device_add+0xe4/0x5a0)
> [ 774.995712] [<c048d75c>] (device_add) from [<c048ddb4>] (device_create_groups_vargs+0xac/0xbc)
> [ 774.995727] [<c048ddb4>] (device_create_groups_vargs) from [<c048dde4>] (device_create_vargs+0x20/0x28)
> [ 774.995740] [<c048dde4>] (device_create_vargs) from [<c02075c8>] (bdi_register_va+0x44/0xfc)
> [ 774.995755] [<c02075c8>] (bdi_register_va) from [<c023d378>] (super_setup_bdi_name+0x48/0xa4)
> [ 774.995771] [<c023d378>] (super_setup_bdi_name) from [<c0312ef4>] (nfs_fill_super+0x1a4/0x204)
> [ 774.995785] [<c0312ef4>] (nfs_fill_super) from [<c03133f0>] (nfs_fs_mount_common+0x140/0x1e8)
> [ 774.995800] [<c03133f0>] (nfs_fs_mount_common) from [<c03335cc>] (nfs4_remote_mount+0x50/0x58)
> [ 774.995816] [<c03335cc>] (nfs4_remote_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> [ 774.995831] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> [ 774.995847] [<c025cba0>] (vfs_kern_mount) from [<c033352c>] (nfs_do_root_mount+0x80/0xa0)
> [ 774.995862] [<c033352c>] (nfs_do_root_mount) from [<c0333818>] (nfs4_try_mount+0x28/0x3c)
> [ 774.995877] [<c0333818>] (nfs4_try_mount) from [<c0313874>] (nfs_fs_mount+0x2cc/0x8c4)
> [ 774.995891] [<c0313874>] (nfs_fs_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> [ 774.995907] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> [ 774.995921] [<c025cba0>] (vfs_kern_mount) from [<c02600f0>] (do_mount+0x158/0xc7c)
> [ 774.995935] [<c02600f0>] (do_mount) from [<c0260f98>] (SyS_mount+0x8c/0xb4)
> [ 774.995949] [<c0260f98>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
> [ 774.995958] ---[ end trace 0665e451f8864ff1 ]---
>
> The mount command is
> mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/local_kernel /usr/src/
>
> the mount command failling with: "mount.nfs: Cannot allocate memory"
>
> Regards
--
Jan Kara <[email protected]>
SUSE Labs, CR

2017-05-02 16:27:08

by Jan Kara

[permalink] [raw]
Subject: Re: [BUG] cannot mount nfs, bisected to 0db10944a76ba ("nfs: Convert to separately allocated bdi")

Hello,

On Fri 28-04-17 11:56:24, Corentin Labbe wrote:
> Since linux next-20170421, mounting nfs give me:
> [ 774.994934] ------------[ cut here ]------------
> [ 774.994975] WARNING: CPU: 1 PID: 10284 at /linux-next/fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x74
> [ 774.994985] sysfs: cannot create duplicate filename '/devices/virtual/bdi/0:32'
> [ 774.994992] Modules linked in: axp20x_usb_power gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
> [ 774.995047] CPU: 1 PID: 10284 Comm: mount.nfs Not tainted 4.11.0-rc4+ #14
> [ 774.995054] Hardware name: Allwinner sun7i (A20) Family
> [ 774.995085] [<c010f19c>] (unwind_backtrace) from [<c010bc74>] (show_stack+0x10/0x14)
> [ 774.995104] [<c010bc74>] (show_stack) from [<c03c6e24>] (dump_stack+0x78/0x8c)
> [ 774.995121] [<c03c6e24>] (dump_stack) from [<c0122200>] (__warn+0xe8/0x100)
> [ 774.995135] [<c0122200>] (__warn) from [<c0122250>] (warn_slowpath_fmt+0x38/0x48)
> [ 774.995150] [<c0122250>] (warn_slowpath_fmt) from [<c02ac178>] (sysfs_warn_dup+0x64/0x74)
> [ 774.995167] [<c02ac178>] (sysfs_warn_dup) from [<c02ac254>] (sysfs_create_dir_ns+0x84/0x94)
> [ 774.995184] [<c02ac254>] (sysfs_create_dir_ns) from [<c03c8b8c>] (kobject_add_internal+0x9c/0x2ec)
> [ 774.995199] [<c03c8b8c>] (kobject_add_internal) from [<c03c8e24>] (kobject_add+0x48/0x98)
> [ 774.995217] [<c03c8e24>] (kobject_add) from [<c048d75c>] (device_add+0xe4/0x5a0)
> [ 774.995232] [<c048d75c>] (device_add) from [<c048ddb4>] (device_create_groups_vargs+0xac/0xbc)
> [ 774.995247] [<c048ddb4>] (device_create_groups_vargs) from [<c048dde4>] (device_create_vargs+0x20/0x28)
> [ 774.995263] [<c048dde4>] (device_create_vargs) from [<c02075c8>] (bdi_register_va+0x44/0xfc)
> [ 774.995280] [<c02075c8>] (bdi_register_va) from [<c023d378>] (super_setup_bdi_name+0x48/0xa4)
> [ 774.995299] [<c023d378>] (super_setup_bdi_name) from [<c0312ef4>] (nfs_fill_super+0x1a4/0x204)
> [ 774.995315] [<c0312ef4>] (nfs_fill_super) from [<c03133f0>] (nfs_fs_mount_common+0x140/0x1e8)
> [ 774.995333] [<c03133f0>] (nfs_fs_mount_common) from [<c03335cc>] (nfs4_remote_mount+0x50/0x58)
> [ 774.995349] [<c03335cc>] (nfs4_remote_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> [ 774.995368] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> [ 774.995385] [<c025cba0>] (vfs_kern_mount) from [<c033352c>] (nfs_do_root_mount+0x80/0xa0)
> [ 774.995400] [<c033352c>] (nfs_do_root_mount) from [<c0333818>] (nfs4_try_mount+0x28/0x3c)
> [ 774.995415] [<c0333818>] (nfs4_try_mount) from [<c0313874>] (nfs_fs_mount+0x2cc/0x8c4)
> [ 774.995430] [<c0313874>] (nfs_fs_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> [ 774.995445] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> [ 774.995461] [<c025cba0>] (vfs_kern_mount) from [<c02600f0>] (do_mount+0x158/0xc7c)
> [ 774.995475] [<c02600f0>] (do_mount) from [<c0260f98>] (SyS_mount+0x8c/0xb4)
> [ 774.995491] [<c0260f98>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
> [ 774.995501] ---[ end trace 0665e451f8864ff0 ]---
...
> The mount command is
> mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/local_kernel /usr/src/
>
> the mount command failling with: "mount.nfs: Cannot allocate memory"

I've tried reproducing this (both with NFSv3 and NFSv4) and failed. Also I
have looked through the code and I fail to see how this could happen. Is
this the only NFS mount that you have on your system? Didn't also the
WARN_ON in super_setup_bdi_name() trigger?

Can you run with the attached debug patch and post full dmesg after the
failure?

Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR


Attachments:
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0001-nfs-Debug-bdi-registration-failure.patch (0.00 B)
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2017-05-02 17:22:28

by Corentin Labbe

[permalink] [raw]
Subject: Re: [BUG] cannot mount nfs, bisected to 0db10944a76ba ("nfs: Convert to separately allocated bdi")

On Tue, May 02, 2017 at 06:27:04PM +0200, Jan Kara wrote:
> Hello,
>
> On Fri 28-04-17 11:56:24, Corentin Labbe wrote:
> > Since linux next-20170421, mounting nfs give me:
> > [ 774.994934] ------------[ cut here ]------------
> > [ 774.994975] WARNING: CPU: 1 PID: 10284 at /linux-next/fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x74
> > [ 774.994985] sysfs: cannot create duplicate filename '/devices/virtual/bdi/0:32'
> > [ 774.994992] Modules linked in: axp20x_usb_power gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
> > [ 774.995047] CPU: 1 PID: 10284 Comm: mount.nfs Not tainted 4.11.0-rc4+ #14
> > [ 774.995054] Hardware name: Allwinner sun7i (A20) Family
> > [ 774.995085] [<c010f19c>] (unwind_backtrace) from [<c010bc74>] (show_stack+0x10/0x14)
> > [ 774.995104] [<c010bc74>] (show_stack) from [<c03c6e24>] (dump_stack+0x78/0x8c)
> > [ 774.995121] [<c03c6e24>] (dump_stack) from [<c0122200>] (__warn+0xe8/0x100)
> > [ 774.995135] [<c0122200>] (__warn) from [<c0122250>] (warn_slowpath_fmt+0x38/0x48)
> > [ 774.995150] [<c0122250>] (warn_slowpath_fmt) from [<c02ac178>] (sysfs_warn_dup+0x64/0x74)
> > [ 774.995167] [<c02ac178>] (sysfs_warn_dup) from [<c02ac254>] (sysfs_create_dir_ns+0x84/0x94)
> > [ 774.995184] [<c02ac254>] (sysfs_create_dir_ns) from [<c03c8b8c>] (kobject_add_internal+0x9c/0x2ec)
> > [ 774.995199] [<c03c8b8c>] (kobject_add_internal) from [<c03c8e24>] (kobject_add+0x48/0x98)
> > [ 774.995217] [<c03c8e24>] (kobject_add) from [<c048d75c>] (device_add+0xe4/0x5a0)
> > [ 774.995232] [<c048d75c>] (device_add) from [<c048ddb4>] (device_create_groups_vargs+0xac/0xbc)
> > [ 774.995247] [<c048ddb4>] (device_create_groups_vargs) from [<c048dde4>] (device_create_vargs+0x20/0x28)
> > [ 774.995263] [<c048dde4>] (device_create_vargs) from [<c02075c8>] (bdi_register_va+0x44/0xfc)
> > [ 774.995280] [<c02075c8>] (bdi_register_va) from [<c023d378>] (super_setup_bdi_name+0x48/0xa4)
> > [ 774.995299] [<c023d378>] (super_setup_bdi_name) from [<c0312ef4>] (nfs_fill_super+0x1a4/0x204)
> > [ 774.995315] [<c0312ef4>] (nfs_fill_super) from [<c03133f0>] (nfs_fs_mount_common+0x140/0x1e8)
> > [ 774.995333] [<c03133f0>] (nfs_fs_mount_common) from [<c03335cc>] (nfs4_remote_mount+0x50/0x58)
> > [ 774.995349] [<c03335cc>] (nfs4_remote_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> > [ 774.995368] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> > [ 774.995385] [<c025cba0>] (vfs_kern_mount) from [<c033352c>] (nfs_do_root_mount+0x80/0xa0)
> > [ 774.995400] [<c033352c>] (nfs_do_root_mount) from [<c0333818>] (nfs4_try_mount+0x28/0x3c)
> > [ 774.995415] [<c0333818>] (nfs4_try_mount) from [<c0313874>] (nfs_fs_mount+0x2cc/0x8c4)
> > [ 774.995430] [<c0313874>] (nfs_fs_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> > [ 774.995445] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> > [ 774.995461] [<c025cba0>] (vfs_kern_mount) from [<c02600f0>] (do_mount+0x158/0xc7c)
> > [ 774.995475] [<c02600f0>] (do_mount) from [<c0260f98>] (SyS_mount+0x8c/0xb4)
> > [ 774.995491] [<c0260f98>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
> > [ 774.995501] ---[ end trace 0665e451f8864ff0 ]---
> ...
> > The mount command is
> > mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/local_kernel /usr/src/
> >
> > the mount command failling with: "mount.nfs: Cannot allocate memory"
>
> I've tried reproducing this (both with NFSv3 and NFSv4) and failed. Also I
> have looked through the code and I fail to see how this could happen. Is
> this the only NFS mount that you have on your system? Didn't also the
> WARN_ON in super_setup_bdi_name() trigger?
>
> Can you run with the attached debug patch and post full dmesg after the
> failure?
>

Hello

I forgot to said that I have 6 nfs mount point.
mount -t nfs -o ro,tcp,hard,intr,async,vers=3 192.168.1.100:/usr/portage /usr/portage/
mount -t nfs -o tcp,hard,intr,async,vers=3 192.168.1.100:/usr/local/portage /usr/local/portage/
mount -t nfs -o tcp,hard,intr,async,vers=3 192.168.1.100:/mnt/tempo/portages/distfiles /usr/portage/distfiles
mount -t nfs -o tcp,hard,intr,async,vers=4 192.168.1.100:/mnt/tempo/portages/cubiedev/packages /usr/portage/packages
mount -t nfs -o tcp,hard,intr,async,vers=4,rsize=4096,wsize=4096 192.168.1.100:/var/tmp/portage/cubie /var/tmp/portage/
mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/tempo/cubie/local_kernel /usr/src/

It's always the last which fail, but strangely inverting the two last made everything ok.

[ 63.424216] Registering bdi 0:29 for server edcdcc00
[ 63.424245] CPU: 1 PID: 2409 Comm: mount.nfs Not tainted 4.11.0-next-20170502+ #100
[ 63.424253] Hardware name: Allwinner sun7i (A20) Family
[ 63.424285] [<c010f268>] (unwind_backtrace) from [<c010bd38>] (show_stack+0x10/0x14)
[ 63.424304] [<c010bd38>] (show_stack) from [<c03c7b68>] (dump_stack+0x78/0x8c)
[ 63.424323] [<c03c7b68>] (dump_stack) from [<c0311664>] (nfs_fill_super+0x1a8/0x224)
[ 63.424339] [<c0311664>] (nfs_fill_super) from [<c0311b7c>] (nfs_fs_mount_common+0x140/0x1e8)
[ 63.424354] [<c0311b7c>] (nfs_fs_mount_common) from [<c0312834>] (nfs_try_mount+0x110/0x268)
[ 63.424369] [<c0312834>] (nfs_try_mount) from [<c0312014>] (nfs_fs_mount+0x2e0/0x8ec)
[ 63.424387] [<c0312014>] (nfs_fs_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 63.424403] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 63.424418] [<c0258ffc>] (vfs_kern_mount) from [<c025c54c>] (do_mount+0x158/0xc7c)
[ 63.424432] [<c025c54c>] (do_mount) from [<c025d3f4>] (SyS_mount+0x8c/0xb4)
[ 63.424448] [<c025d3f4>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 63.474416] Registering bdi 0:30 for server ee40b800
[ 63.474442] CPU: 1 PID: 2413 Comm: mount.nfs Not tainted 4.11.0-next-20170502+ #100
[ 63.474450] Hardware name: Allwinner sun7i (A20) Family
[ 63.474488] [<c010f268>] (unwind_backtrace) from [<c010bd38>] (show_stack+0x10/0x14)
[ 63.474507] [<c010bd38>] (show_stack) from [<c03c7b68>] (dump_stack+0x78/0x8c)
[ 63.474527] [<c03c7b68>] (dump_stack) from [<c0311664>] (nfs_fill_super+0x1a8/0x224)
[ 63.474544] [<c0311664>] (nfs_fill_super) from [<c0311b7c>] (nfs_fs_mount_common+0x140/0x1e8)
[ 63.474559] [<c0311b7c>] (nfs_fs_mount_common) from [<c0312834>] (nfs_try_mount+0x110/0x268)
[ 63.474574] [<c0312834>] (nfs_try_mount) from [<c0312014>] (nfs_fs_mount+0x2e0/0x8ec)
[ 63.474591] [<c0312014>] (nfs_fs_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 63.474609] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 63.474625] [<c0258ffc>] (vfs_kern_mount) from [<c025c54c>] (do_mount+0x158/0xc7c)
[ 63.474640] [<c025c54c>] (do_mount) from [<c025d3f4>] (SyS_mount+0x8c/0xb4)
[ 63.474656] [<c025d3f4>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 63.532851] Registering bdi 0:31 for server edd48c00
[ 63.532877] CPU: 1 PID: 2416 Comm: mount.nfs Not tainted 4.11.0-next-20170502+ #100
[ 63.532885] Hardware name: Allwinner sun7i (A20) Family
[ 63.532924] [<c010f268>] (unwind_backtrace) from [<c010bd38>] (show_stack+0x10/0x14)
[ 63.532946] [<c010bd38>] (show_stack) from [<c03c7b68>] (dump_stack+0x78/0x8c)
[ 63.532967] [<c03c7b68>] (dump_stack) from [<c0311664>] (nfs_fill_super+0x1a8/0x224)
[ 63.532984] [<c0311664>] (nfs_fill_super) from [<c0311b7c>] (nfs_fs_mount_common+0x140/0x1e8)
[ 63.532999] [<c0311b7c>] (nfs_fs_mount_common) from [<c0312834>] (nfs_try_mount+0x110/0x268)
[ 63.533014] [<c0312834>] (nfs_try_mount) from [<c0312014>] (nfs_fs_mount+0x2e0/0x8ec)
[ 63.533032] [<c0312014>] (nfs_fs_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 63.533049] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 63.533064] [<c0258ffc>] (vfs_kern_mount) from [<c025c54c>] (do_mount+0x158/0xc7c)
[ 63.533079] [<c025c54c>] (do_mount) from [<c025d3f4>] (SyS_mount+0x8c/0xb4)
[ 63.533096] [<c025d3f4>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 63.607887] Registering bdi 0:32 for server edc7c400
[ 63.607914] CPU: 1 PID: 2419 Comm: mount.nfs Not tainted 4.11.0-next-20170502+ #100
[ 63.607923] Hardware name: Allwinner sun7i (A20) Family
[ 63.607955] [<c010f268>] (unwind_backtrace) from [<c010bd38>] (show_stack+0x10/0x14)
[ 63.607975] [<c010bd38>] (show_stack) from [<c03c7b68>] (dump_stack+0x78/0x8c)
[ 63.607995] [<c03c7b68>] (dump_stack) from [<c0311664>] (nfs_fill_super+0x1a8/0x224)
[ 63.608012] [<c0311664>] (nfs_fill_super) from [<c0311b7c>] (nfs_fs_mount_common+0x140/0x1e8)
[ 63.608028] [<c0311b7c>] (nfs_fs_mount_common) from [<c0332014>] (nfs4_remote_mount+0x50/0x58)
[ 63.608044] [<c0332014>] (nfs4_remote_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 63.608060] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 63.608077] [<c0258ffc>] (vfs_kern_mount) from [<c0331f74>] (nfs_do_root_mount+0x80/0xa0)
[ 63.608092] [<c0331f74>] (nfs_do_root_mount) from [<c0332260>] (nfs4_try_mount+0x28/0x3c)
[ 63.608105] [<c0332260>] (nfs4_try_mount) from [<c0312014>] (nfs_fs_mount+0x2e0/0x8ec)
[ 63.608121] [<c0312014>] (nfs_fs_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 63.608135] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 63.608150] [<c0258ffc>] (vfs_kern_mount) from [<c025c54c>] (do_mount+0x158/0xc7c)
[ 63.608164] [<c025c54c>] (do_mount) from [<c025d3f4>] (SyS_mount+0x8c/0xb4)
[ 63.608181] [<c025d3f4>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 63.711978] Unregistering bdi 0:32
[ 63.712008] CPU: 1 PID: 2419 Comm: mount.nfs Not tainted 4.11.0-next-20170502+ #100
[ 63.712016] Hardware name: Allwinner sun7i (A20) Family
[ 63.712054] [<c010f268>] (unwind_backtrace) from [<c010bd38>] (show_stack+0x10/0x14)
[ 63.712072] [<c010bd38>] (show_stack) from [<c03c7b68>] (dump_stack+0x78/0x8c)
[ 63.712091] [<c03c7b68>] (dump_stack) from [<c0204120>] (bdi_unregister+0x34/0x18c)
[ 63.712107] [<c0204120>] (bdi_unregister) from [<c020436c>] (bdi_put+0xf4/0x13c)
[ 63.712124] [<c020436c>] (bdi_put) from [<c0239728>] (generic_shutdown_super+0xdc/0xf8)
[ 63.712143] [<c0239728>] (generic_shutdown_super) from [<c0311cc4>] (nfs_kill_super+0x14/0x30)
[ 63.712160] [<c0311cc4>] (nfs_kill_super) from [<c0239e9c>] (deactivate_locked_super+0x58/0x7c)
[ 63.712176] [<c0239e9c>] (deactivate_locked_super) from [<c025945c>] (cleanup_mnt+0x38/0x7c)
[ 63.712192] [<c025945c>] (cleanup_mnt) from [<c013fd9c>] (task_work_run+0xc4/0xf8)
[ 63.712209] [<c013fd9c>] (task_work_run) from [<c010b61c>] (do_work_pending+0x7c/0xa4)
[ 63.712225] [<c010b61c>] (do_work_pending) from [<c0107894>] (slow_work_pending+0xc/0x20)
[ 63.795383] Registering bdi 0:32 for server edd49800
[ 63.795409] CPU: 1 PID: 2419 Comm: mount.nfs Not tainted 4.11.0-next-20170502+ #100
[ 63.795417] Hardware name: Allwinner sun7i (A20) Family
[ 63.795455] [<c010f268>] (unwind_backtrace) from [<c010bd38>] (show_stack+0x10/0x14)
[ 63.795475] [<c010bd38>] (show_stack) from [<c03c7b68>] (dump_stack+0x78/0x8c)
[ 63.795496] [<c03c7b68>] (dump_stack) from [<c0311664>] (nfs_fill_super+0x1a8/0x224)
[ 63.795513] [<c0311664>] (nfs_fill_super) from [<c0311b7c>] (nfs_fs_mount_common+0x140/0x1e8)
[ 63.795528] [<c0311b7c>] (nfs_fs_mount_common) from [<c0312834>] (nfs_try_mount+0x110/0x268)
[ 63.795543] [<c0312834>] (nfs_try_mount) from [<c0312014>] (nfs_fs_mount+0x2e0/0x8ec)
[ 63.795561] [<c0312014>] (nfs_fs_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 63.795578] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 63.795594] [<c0258ffc>] (vfs_kern_mount) from [<c025c54c>] (do_mount+0x158/0xc7c)
[ 63.795609] [<c025c54c>] (do_mount) from [<c025d3f4>] (SyS_mount+0x8c/0xb4)
[ 63.795626] [<c025d3f4>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 63.862429] Registering bdi 0:33 for server edd4a400
[ 63.862455] CPU: 1 PID: 2429 Comm: mount.nfs Not tainted 4.11.0-next-20170502+ #100
[ 63.862463] Hardware name: Allwinner sun7i (A20) Family
[ 63.862502] [<c010f268>] (unwind_backtrace) from [<c010bd38>] (show_stack+0x10/0x14)
[ 63.862521] [<c010bd38>] (show_stack) from [<c03c7b68>] (dump_stack+0x78/0x8c)
[ 63.862541] [<c03c7b68>] (dump_stack) from [<c0311664>] (nfs_fill_super+0x1a8/0x224)
[ 63.862560] [<c0311664>] (nfs_fill_super) from [<c0311b7c>] (nfs_fs_mount_common+0x140/0x1e8)
[ 63.862575] [<c0311b7c>] (nfs_fs_mount_common) from [<c0332014>] (nfs4_remote_mount+0x50/0x58)
[ 63.862593] [<c0332014>] (nfs4_remote_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 63.862611] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 63.862628] [<c0258ffc>] (vfs_kern_mount) from [<c0331f74>] (nfs_do_root_mount+0x80/0xa0)
[ 63.862643] [<c0331f74>] (nfs_do_root_mount) from [<c0332260>] (nfs4_try_mount+0x28/0x3c)
[ 63.862657] [<c0332260>] (nfs4_try_mount) from [<c0312014>] (nfs_fs_mount+0x2e0/0x8ec)
[ 63.862672] [<c0312014>] (nfs_fs_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 63.862686] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 63.862701] [<c0258ffc>] (vfs_kern_mount) from [<c025c54c>] (do_mount+0x158/0xc7c)
[ 63.862716] [<c025c54c>] (do_mount) from [<c025d3f4>] (SyS_mount+0x8c/0xb4)
[ 63.862732] [<c025d3f4>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 64.094628] Registering bdi 0:33 for server edc87800
[ 64.094655] CPU: 1 PID: 2437 Comm: mount.nfs Not tainted 4.11.0-next-20170502+ #100
[ 64.094663] Hardware name: Allwinner sun7i (A20) Family
[ 64.094702] [<c010f268>] (unwind_backtrace) from [<c010bd38>] (show_stack+0x10/0x14)
[ 64.094722] [<c010bd38>] (show_stack) from [<c03c7b68>] (dump_stack+0x78/0x8c)
[ 64.094742] [<c03c7b68>] (dump_stack) from [<c0311664>] (nfs_fill_super+0x1a8/0x224)
[ 64.094760] [<c0311664>] (nfs_fill_super) from [<c0311b7c>] (nfs_fs_mount_common+0x140/0x1e8)
[ 64.094777] [<c0311b7c>] (nfs_fs_mount_common) from [<c0332014>] (nfs4_remote_mount+0x50/0x58)
[ 64.094794] [<c0332014>] (nfs4_remote_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 64.094812] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 64.094829] [<c0258ffc>] (vfs_kern_mount) from [<c0331f74>] (nfs_do_root_mount+0x80/0xa0)
[ 64.094844] [<c0331f74>] (nfs_do_root_mount) from [<c0332260>] (nfs4_try_mount+0x28/0x3c)
[ 64.094858] [<c0332260>] (nfs4_try_mount) from [<c0312014>] (nfs_fs_mount+0x2e0/0x8ec)
[ 64.094873] [<c0312014>] (nfs_fs_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 64.094888] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 64.094902] [<c0258ffc>] (vfs_kern_mount) from [<c025c54c>] (do_mount+0x158/0xc7c)
[ 64.094917] [<c025c54c>] (do_mount) from [<c025d3f4>] (SyS_mount+0x8c/0xb4)
[ 64.094934] [<c025d3f4>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 64.095053] ------------[ cut here ]------------
[ 64.095072] WARNING: CPU: 1 PID: 2437 at /mnt/linux-next/fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x74
[ 64.095081] sysfs: cannot create duplicate filename '/devices/virtual/bdi/0:33'
[ 64.095088] Modules linked in: axp20x_usb_power axp20x_ac_power axp20x_adc gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
[ 64.095154] CPU: 1 PID: 2437 Comm: mount.nfs Not tainted 4.11.0-next-20170502+ #100
[ 64.095162] Hardware name: Allwinner sun7i (A20) Family
[ 64.095179] [<c010f268>] (unwind_backtrace) from [<c010bd38>] (show_stack+0x10/0x14)
[ 64.095194] [<c010bd38>] (show_stack) from [<c03c7b68>] (dump_stack+0x78/0x8c)
[ 64.095210] [<c03c7b68>] (dump_stack) from [<c01222d4>] (__warn+0xe8/0x100)
[ 64.095224] [<c01222d4>] (__warn) from [<c0122324>] (warn_slowpath_fmt+0x38/0x48)
[ 64.095240] [<c0122324>] (warn_slowpath_fmt) from [<c02a8d4c>] (sysfs_warn_dup+0x64/0x74)
[ 64.095256] [<c02a8d4c>] (sysfs_warn_dup) from [<c02a8e28>] (sysfs_create_dir_ns+0x84/0x94)
[ 64.095273] [<c02a8e28>] (sysfs_create_dir_ns) from [<c03c98d0>] (kobject_add_internal+0x9c/0x2ec)
[ 64.095290] [<c03c98d0>] (kobject_add_internal) from [<c03c9b68>] (kobject_add+0x48/0x98)
[ 64.095309] [<c03c9b68>] (kobject_add) from [<c048f7bc>] (device_add+0xe4/0x5a0)
[ 64.095326] [<c048f7bc>] (device_add) from [<c048fe14>] (device_create_groups_vargs+0xac/0xbc)
[ 64.095341] [<c048fe14>] (device_create_groups_vargs) from [<c048fe44>] (device_create_vargs+0x20/0x28)
[ 64.095358] [<c048fe44>] (device_create_vargs) from [<c0203ab0>] (bdi_register_va+0x44/0xfc)
[ 64.095375] [<c0203ab0>] (bdi_register_va) from [<c0239a4c>] (super_setup_bdi_name+0x44/0xa0)
[ 64.095393] [<c0239a4c>] (super_setup_bdi_name) from [<c0311680>] (nfs_fill_super+0x1c4/0x224)
[ 64.095409] [<c0311680>] (nfs_fill_super) from [<c0311b7c>] (nfs_fs_mount_common+0x140/0x1e8)
[ 64.095423] [<c0311b7c>] (nfs_fs_mount_common) from [<c0332014>] (nfs4_remote_mount+0x50/0x58)
[ 64.095437] [<c0332014>] (nfs4_remote_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 64.095451] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 64.095467] [<c0258ffc>] (vfs_kern_mount) from [<c0331f74>] (nfs_do_root_mount+0x80/0xa0)
[ 64.095482] [<c0331f74>] (nfs_do_root_mount) from [<c0332260>] (nfs4_try_mount+0x28/0x3c)
[ 64.095496] [<c0332260>] (nfs4_try_mount) from [<c0312014>] (nfs_fs_mount+0x2e0/0x8ec)
[ 64.095511] [<c0312014>] (nfs_fs_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 64.095525] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 64.095538] [<c0258ffc>] (vfs_kern_mount) from [<c025c54c>] (do_mount+0x158/0xc7c)
[ 64.095553] [<c025c54c>] (do_mount) from [<c025d3f4>] (SyS_mount+0x8c/0xb4)
[ 64.095568] [<c025d3f4>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 64.095577] ---[ end trace 5cd276530ddd30a7 ]---
[ 64.095588] ------------[ cut here ]------------
[ 64.095603] WARNING: CPU: 1 PID: 2437 at /mnt/linux-next/lib/kobject.c:240 kobject_add_internal+0x274/0x2ec
[ 64.095612] kobject_add_internal failed for 0:33 with -EEXIST, don't try to register things with the same name in the same directory.
[ 64.095618] Modules linked in: axp20x_usb_power axp20x_ac_power axp20x_adc gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
[ 64.095679] CPU: 1 PID: 2437 Comm: mount.nfs Tainted: G W 4.11.0-next-20170502+ #100
[ 64.095687] Hardware name: Allwinner sun7i (A20) Family
[ 64.095702] [<c010f268>] (unwind_backtrace) from [<c010bd38>] (show_stack+0x10/0x14)
[ 64.095716] [<c010bd38>] (show_stack) from [<c03c7b68>] (dump_stack+0x78/0x8c)
[ 64.095730] [<c03c7b68>] (dump_stack) from [<c01222d4>] (__warn+0xe8/0x100)
[ 64.095743] [<c01222d4>] (__warn) from [<c0122324>] (warn_slowpath_fmt+0x38/0x48)
[ 64.095758] [<c0122324>] (warn_slowpath_fmt) from [<c03c9aa8>] (kobject_add_internal+0x274/0x2ec)
[ 64.095775] [<c03c9aa8>] (kobject_add_internal) from [<c03c9b68>] (kobject_add+0x48/0x98)
[ 64.095790] [<c03c9b68>] (kobject_add) from [<c048f7bc>] (device_add+0xe4/0x5a0)
[ 64.095806] [<c048f7bc>] (device_add) from [<c048fe14>] (device_create_groups_vargs+0xac/0xbc)
[ 64.095821] [<c048fe14>] (device_create_groups_vargs) from [<c048fe44>] (device_create_vargs+0x20/0x28)
[ 64.095836] [<c048fe44>] (device_create_vargs) from [<c0203ab0>] (bdi_register_va+0x44/0xfc)
[ 64.095851] [<c0203ab0>] (bdi_register_va) from [<c0239a4c>] (super_setup_bdi_name+0x44/0xa0)
[ 64.095868] [<c0239a4c>] (super_setup_bdi_name) from [<c0311680>] (nfs_fill_super+0x1c4/0x224)
[ 64.095883] [<c0311680>] (nfs_fill_super) from [<c0311b7c>] (nfs_fs_mount_common+0x140/0x1e8)
[ 64.095897] [<c0311b7c>] (nfs_fs_mount_common) from [<c0332014>] (nfs4_remote_mount+0x50/0x58)
[ 64.095911] [<c0332014>] (nfs4_remote_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 64.095926] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 64.095940] [<c0258ffc>] (vfs_kern_mount) from [<c0331f74>] (nfs_do_root_mount+0x80/0xa0)
[ 64.095955] [<c0331f74>] (nfs_do_root_mount) from [<c0332260>] (nfs4_try_mount+0x28/0x3c)
[ 64.095969] [<c0332260>] (nfs4_try_mount) from [<c0312014>] (nfs_fs_mount+0x2e0/0x8ec)
[ 64.095984] [<c0312014>] (nfs_fs_mount) from [<c023b66c>] (mount_fs+0x14/0xa4)
[ 64.095999] [<c023b66c>] (mount_fs) from [<c0258ffc>] (vfs_kern_mount+0x54/0x128)
[ 64.096012] [<c0258ffc>] (vfs_kern_mount) from [<c025c54c>] (do_mount+0x158/0xc7c)
[ 64.096026] [<c025c54c>] (do_mount) from [<c025d3f4>] (SyS_mount+0x8c/0xb4)
[ 64.096041] [<c025d3f4>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
[ 64.096049] ---[ end trace 5cd276530ddd30a8 ]---


2017-05-03 11:44:58

by Jan Kara

[permalink] [raw]
Subject: Re: [BUG] cannot mount nfs, bisected to 0db10944a76ba ("nfs: Convert to separately allocated bdi")

On Tue 02-05-17 19:22:22, Corentin Labbe wrote:
> On Tue, May 02, 2017 at 06:27:04PM +0200, Jan Kara wrote:
> > Hello,
> >
> > On Fri 28-04-17 11:56:24, Corentin Labbe wrote:
> > > Since linux next-20170421, mounting nfs give me:
> > > [ 774.994934] ------------[ cut here ]------------
> > > [ 774.994975] WARNING: CPU: 1 PID: 10284 at /linux-next/fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x74
> > > [ 774.994985] sysfs: cannot create duplicate filename '/devices/virtual/bdi/0:32'
> > > [ 774.994992] Modules linked in: axp20x_usb_power gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
> > > [ 774.995047] CPU: 1 PID: 10284 Comm: mount.nfs Not tainted 4.11.0-rc4+ #14
> > > [ 774.995054] Hardware name: Allwinner sun7i (A20) Family
> > > [ 774.995085] [<c010f19c>] (unwind_backtrace) from [<c010bc74>] (show_stack+0x10/0x14)
> > > [ 774.995104] [<c010bc74>] (show_stack) from [<c03c6e24>] (dump_stack+0x78/0x8c)
> > > [ 774.995121] [<c03c6e24>] (dump_stack) from [<c0122200>] (__warn+0xe8/0x100)
> > > [ 774.995135] [<c0122200>] (__warn) from [<c0122250>] (warn_slowpath_fmt+0x38/0x48)
> > > [ 774.995150] [<c0122250>] (warn_slowpath_fmt) from [<c02ac178>] (sysfs_warn_dup+0x64/0x74)
> > > [ 774.995167] [<c02ac178>] (sysfs_warn_dup) from [<c02ac254>] (sysfs_create_dir_ns+0x84/0x94)
> > > [ 774.995184] [<c02ac254>] (sysfs_create_dir_ns) from [<c03c8b8c>] (kobject_add_internal+0x9c/0x2ec)
> > > [ 774.995199] [<c03c8b8c>] (kobject_add_internal) from [<c03c8e24>] (kobject_add+0x48/0x98)
> > > [ 774.995217] [<c03c8e24>] (kobject_add) from [<c048d75c>] (device_add+0xe4/0x5a0)
> > > [ 774.995232] [<c048d75c>] (device_add) from [<c048ddb4>] (device_create_groups_vargs+0xac/0xbc)
> > > [ 774.995247] [<c048ddb4>] (device_create_groups_vargs) from [<c048dde4>] (device_create_vargs+0x20/0x28)
> > > [ 774.995263] [<c048dde4>] (device_create_vargs) from [<c02075c8>] (bdi_register_va+0x44/0xfc)
> > > [ 774.995280] [<c02075c8>] (bdi_register_va) from [<c023d378>] (super_setup_bdi_name+0x48/0xa4)
> > > [ 774.995299] [<c023d378>] (super_setup_bdi_name) from [<c0312ef4>] (nfs_fill_super+0x1a4/0x204)
> > > [ 774.995315] [<c0312ef4>] (nfs_fill_super) from [<c03133f0>] (nfs_fs_mount_common+0x140/0x1e8)
> > > [ 774.995333] [<c03133f0>] (nfs_fs_mount_common) from [<c03335cc>] (nfs4_remote_mount+0x50/0x58)
> > > [ 774.995349] [<c03335cc>] (nfs4_remote_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> > > [ 774.995368] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> > > [ 774.995385] [<c025cba0>] (vfs_kern_mount) from [<c033352c>] (nfs_do_root_mount+0x80/0xa0)
> > > [ 774.995400] [<c033352c>] (nfs_do_root_mount) from [<c0333818>] (nfs4_try_mount+0x28/0x3c)
> > > [ 774.995415] [<c0333818>] (nfs4_try_mount) from [<c0313874>] (nfs_fs_mount+0x2cc/0x8c4)
> > > [ 774.995430] [<c0313874>] (nfs_fs_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> > > [ 774.995445] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> > > [ 774.995461] [<c025cba0>] (vfs_kern_mount) from [<c02600f0>] (do_mount+0x158/0xc7c)
> > > [ 774.995475] [<c02600f0>] (do_mount) from [<c0260f98>] (SyS_mount+0x8c/0xb4)
> > > [ 774.995491] [<c0260f98>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
> > > [ 774.995501] ---[ end trace 0665e451f8864ff0 ]---
> > ...
> > > The mount command is
> > > mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/local_kernel /usr/src/
> > >
> > > the mount command failling with: "mount.nfs: Cannot allocate memory"
> >
> > I've tried reproducing this (both with NFSv3 and NFSv4) and failed. Also I
> > have looked through the code and I fail to see how this could happen. Is
> > this the only NFS mount that you have on your system? Didn't also the
> > WARN_ON in super_setup_bdi_name() trigger?
> >
> > Can you run with the attached debug patch and post full dmesg after the
> > failure?
> >
>
> Hello
>
> I forgot to said that I have 6 nfs mount point.
> mount -t nfs -o ro,tcp,hard,intr,async,vers=3 192.168.1.100:/usr/portage /usr/portage/
> mount -t nfs -o tcp,hard,intr,async,vers=3 192.168.1.100:/usr/local/portage /usr/local/portage/
> mount -t nfs -o tcp,hard,intr,async,vers=3 192.168.1.100:/mnt/tempo/portages/distfiles /usr/portage/distfiles
> mount -t nfs -o tcp,hard,intr,async,vers=4 192.168.1.100:/mnt/tempo/portages/cubiedev/packages /usr/portage/packages
> mount -t nfs -o tcp,hard,intr,async,vers=4,rsize=4096,wsize=4096 192.168.1.100:/var/tmp/portage/cubie /var/tmp/portage/
> mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/tempo/cubie/local_kernel /usr/src/
>
> It's always the last which fail, but strangely inverting the two last
> made everything ok.

Thanks for more info and the debug data. I still was not able to reproduce
the issue but after pondering my head on this for some time I have found a
bug in NFS conversion which can possibly cause the behavior you observe.
Does the attached patch fix the problem for you?

If it does not, can you also post /proc/mounts and /etc/exports from you
NFS server?

Honza


--
Jan Kara <[email protected]>
SUSE Labs, CR


Attachments:
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0001-nfs-Fix-bdi-handling-for-cloned-superblocks.patch (0.00 B)
Download all attachments

2017-05-03 17:19:21

by Corentin Labbe

[permalink] [raw]
Subject: Re: [BUG] cannot mount nfs, bisected to 0db10944a76ba ("nfs: Convert to separately allocated bdi")

On Wed, May 03, 2017 at 01:44:54PM +0200, Jan Kara wrote:
> On Tue 02-05-17 19:22:22, Corentin Labbe wrote:
> > On Tue, May 02, 2017 at 06:27:04PM +0200, Jan Kara wrote:
> > > Hello,
> > >
> > > On Fri 28-04-17 11:56:24, Corentin Labbe wrote:
> > > > Since linux next-20170421, mounting nfs give me:
> > > > [ 774.994934] ------------[ cut here ]------------
> > > > [ 774.994975] WARNING: CPU: 1 PID: 10284 at /linux-next/fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x74
> > > > [ 774.994985] sysfs: cannot create duplicate filename '/devices/virtual/bdi/0:32'
> > > > [ 774.994992] Modules linked in: axp20x_usb_power gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
> > > > [ 774.995047] CPU: 1 PID: 10284 Comm: mount.nfs Not tainted 4.11.0-rc4+ #14
> > > > [ 774.995054] Hardware name: Allwinner sun7i (A20) Family
> > > > [ 774.995085] [<c010f19c>] (unwind_backtrace) from [<c010bc74>] (show_stack+0x10/0x14)
> > > > [ 774.995104] [<c010bc74>] (show_stack) from [<c03c6e24>] (dump_stack+0x78/0x8c)
> > > > [ 774.995121] [<c03c6e24>] (dump_stack) from [<c0122200>] (__warn+0xe8/0x100)
> > > > [ 774.995135] [<c0122200>] (__warn) from [<c0122250>] (warn_slowpath_fmt+0x38/0x48)
> > > > [ 774.995150] [<c0122250>] (warn_slowpath_fmt) from [<c02ac178>] (sysfs_warn_dup+0x64/0x74)
> > > > [ 774.995167] [<c02ac178>] (sysfs_warn_dup) from [<c02ac254>] (sysfs_create_dir_ns+0x84/0x94)
> > > > [ 774.995184] [<c02ac254>] (sysfs_create_dir_ns) from [<c03c8b8c>] (kobject_add_internal+0x9c/0x2ec)
> > > > [ 774.995199] [<c03c8b8c>] (kobject_add_internal) from [<c03c8e24>] (kobject_add+0x48/0x98)
> > > > [ 774.995217] [<c03c8e24>] (kobject_add) from [<c048d75c>] (device_add+0xe4/0x5a0)
> > > > [ 774.995232] [<c048d75c>] (device_add) from [<c048ddb4>] (device_create_groups_vargs+0xac/0xbc)
> > > > [ 774.995247] [<c048ddb4>] (device_create_groups_vargs) from [<c048dde4>] (device_create_vargs+0x20/0x28)
> > > > [ 774.995263] [<c048dde4>] (device_create_vargs) from [<c02075c8>] (bdi_register_va+0x44/0xfc)
> > > > [ 774.995280] [<c02075c8>] (bdi_register_va) from [<c023d378>] (super_setup_bdi_name+0x48/0xa4)
> > > > [ 774.995299] [<c023d378>] (super_setup_bdi_name) from [<c0312ef4>] (nfs_fill_super+0x1a4/0x204)
> > > > [ 774.995315] [<c0312ef4>] (nfs_fill_super) from [<c03133f0>] (nfs_fs_mount_common+0x140/0x1e8)
> > > > [ 774.995333] [<c03133f0>] (nfs_fs_mount_common) from [<c03335cc>] (nfs4_remote_mount+0x50/0x58)
> > > > [ 774.995349] [<c03335cc>] (nfs4_remote_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> > > > [ 774.995368] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> > > > [ 774.995385] [<c025cba0>] (vfs_kern_mount) from [<c033352c>] (nfs_do_root_mount+0x80/0xa0)
> > > > [ 774.995400] [<c033352c>] (nfs_do_root_mount) from [<c0333818>] (nfs4_try_mount+0x28/0x3c)
> > > > [ 774.995415] [<c0333818>] (nfs4_try_mount) from [<c0313874>] (nfs_fs_mount+0x2cc/0x8c4)
> > > > [ 774.995430] [<c0313874>] (nfs_fs_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> > > > [ 774.995445] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> > > > [ 774.995461] [<c025cba0>] (vfs_kern_mount) from [<c02600f0>] (do_mount+0x158/0xc7c)
> > > > [ 774.995475] [<c02600f0>] (do_mount) from [<c0260f98>] (SyS_mount+0x8c/0xb4)
> > > > [ 774.995491] [<c0260f98>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
> > > > [ 774.995501] ---[ end trace 0665e451f8864ff0 ]---
> > > ...
> > > > The mount command is
> > > > mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/local_kernel /usr/src/
> > > >
> > > > the mount command failling with: "mount.nfs: Cannot allocate memory"
> > >
> > > I've tried reproducing this (both with NFSv3 and NFSv4) and failed. Also I
> > > have looked through the code and I fail to see how this could happen. Is
> > > this the only NFS mount that you have on your system? Didn't also the
> > > WARN_ON in super_setup_bdi_name() trigger?
> > >
> > > Can you run with the attached debug patch and post full dmesg after the
> > > failure?
> > >
> >
> > Hello
> >
> > I forgot to said that I have 6 nfs mount point.
> > mount -t nfs -o ro,tcp,hard,intr,async,vers=3 192.168.1.100:/usr/portage /usr/portage/
> > mount -t nfs -o tcp,hard,intr,async,vers=3 192.168.1.100:/usr/local/portage /usr/local/portage/
> > mount -t nfs -o tcp,hard,intr,async,vers=3 192.168.1.100:/mnt/tempo/portages/distfiles /usr/portage/distfiles
> > mount -t nfs -o tcp,hard,intr,async,vers=4 192.168.1.100:/mnt/tempo/portages/cubiedev/packages /usr/portage/packages
> > mount -t nfs -o tcp,hard,intr,async,vers=4,rsize=4096,wsize=4096 192.168.1.100:/var/tmp/portage/cubie /var/tmp/portage/
> > mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/tempo/cubie/local_kernel /usr/src/
> >
> > It's always the last which fail, but strangely inverting the two last
> > made everything ok.
>
> Thanks for more info and the debug data. I still was not able to reproduce
> the issue but after pondering my head on this for some time I have found a
> bug in NFS conversion which can possibly cause the behavior you observe.
> Does the attached patch fix the problem for you?
>
> If it does not, can you also post /proc/mounts and /etc/exports from you
> NFS server?
>

This patch fix the issue

Thanks
Corentin Labbe

2017-05-04 06:59:32

by Jan Kara

[permalink] [raw]
Subject: Re: [BUG] cannot mount nfs, bisected to 0db10944a76ba ("nfs: Convert to separately allocated bdi")

On Wed 03-05-17 19:19:11, Corentin Labbe wrote:
> On Wed, May 03, 2017 at 01:44:54PM +0200, Jan Kara wrote:
> > On Tue 02-05-17 19:22:22, Corentin Labbe wrote:
> > > On Tue, May 02, 2017 at 06:27:04PM +0200, Jan Kara wrote:
> > > > Hello,
> > > >
> > > > On Fri 28-04-17 11:56:24, Corentin Labbe wrote:
> > > > > Since linux next-20170421, mounting nfs give me:
> > > > > [ 774.994934] ------------[ cut here ]------------
> > > > > [ 774.994975] WARNING: CPU: 1 PID: 10284 at /linux-next/fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x74
> > > > > [ 774.994985] sysfs: cannot create duplicate filename '/devices/virtual/bdi/0:32'
> > > > > [ 774.994992] Modules linked in: axp20x_usb_power gpio_axp209 nvmem_sunxi_sid sun4i_dma sun4i_ss virt_dma
> > > > > [ 774.995047] CPU: 1 PID: 10284 Comm: mount.nfs Not tainted 4.11.0-rc4+ #14
> > > > > [ 774.995054] Hardware name: Allwinner sun7i (A20) Family
> > > > > [ 774.995085] [<c010f19c>] (unwind_backtrace) from [<c010bc74>] (show_stack+0x10/0x14)
> > > > > [ 774.995104] [<c010bc74>] (show_stack) from [<c03c6e24>] (dump_stack+0x78/0x8c)
> > > > > [ 774.995121] [<c03c6e24>] (dump_stack) from [<c0122200>] (__warn+0xe8/0x100)
> > > > > [ 774.995135] [<c0122200>] (__warn) from [<c0122250>] (warn_slowpath_fmt+0x38/0x48)
> > > > > [ 774.995150] [<c0122250>] (warn_slowpath_fmt) from [<c02ac178>] (sysfs_warn_dup+0x64/0x74)
> > > > > [ 774.995167] [<c02ac178>] (sysfs_warn_dup) from [<c02ac254>] (sysfs_create_dir_ns+0x84/0x94)
> > > > > [ 774.995184] [<c02ac254>] (sysfs_create_dir_ns) from [<c03c8b8c>] (kobject_add_internal+0x9c/0x2ec)
> > > > > [ 774.995199] [<c03c8b8c>] (kobject_add_internal) from [<c03c8e24>] (kobject_add+0x48/0x98)
> > > > > [ 774.995217] [<c03c8e24>] (kobject_add) from [<c048d75c>] (device_add+0xe4/0x5a0)
> > > > > [ 774.995232] [<c048d75c>] (device_add) from [<c048ddb4>] (device_create_groups_vargs+0xac/0xbc)
> > > > > [ 774.995247] [<c048ddb4>] (device_create_groups_vargs) from [<c048dde4>] (device_create_vargs+0x20/0x28)
> > > > > [ 774.995263] [<c048dde4>] (device_create_vargs) from [<c02075c8>] (bdi_register_va+0x44/0xfc)
> > > > > [ 774.995280] [<c02075c8>] (bdi_register_va) from [<c023d378>] (super_setup_bdi_name+0x48/0xa4)
> > > > > [ 774.995299] [<c023d378>] (super_setup_bdi_name) from [<c0312ef4>] (nfs_fill_super+0x1a4/0x204)
> > > > > [ 774.995315] [<c0312ef4>] (nfs_fill_super) from [<c03133f0>] (nfs_fs_mount_common+0x140/0x1e8)
> > > > > [ 774.995333] [<c03133f0>] (nfs_fs_mount_common) from [<c03335cc>] (nfs4_remote_mount+0x50/0x58)
> > > > > [ 774.995349] [<c03335cc>] (nfs4_remote_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> > > > > [ 774.995368] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> > > > > [ 774.995385] [<c025cba0>] (vfs_kern_mount) from [<c033352c>] (nfs_do_root_mount+0x80/0xa0)
> > > > > [ 774.995400] [<c033352c>] (nfs_do_root_mount) from [<c0333818>] (nfs4_try_mount+0x28/0x3c)
> > > > > [ 774.995415] [<c0333818>] (nfs4_try_mount) from [<c0313874>] (nfs_fs_mount+0x2cc/0x8c4)
> > > > > [ 774.995430] [<c0313874>] (nfs_fs_mount) from [<c023ef98>] (mount_fs+0x14/0xa4)
> > > > > [ 774.995445] [<c023ef98>] (mount_fs) from [<c025cba0>] (vfs_kern_mount+0x54/0x128)
> > > > > [ 774.995461] [<c025cba0>] (vfs_kern_mount) from [<c02600f0>] (do_mount+0x158/0xc7c)
> > > > > [ 774.995475] [<c02600f0>] (do_mount) from [<c0260f98>] (SyS_mount+0x8c/0xb4)
> > > > > [ 774.995491] [<c0260f98>] (SyS_mount) from [<c0107840>] (ret_fast_syscall+0x0/0x3c)
> > > > > [ 774.995501] ---[ end trace 0665e451f8864ff0 ]---
> > > > ...
> > > > > The mount command is
> > > > > mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/local_kernel /usr/src/
> > > > >
> > > > > the mount command failling with: "mount.nfs: Cannot allocate memory"
> > > >
> > > > I've tried reproducing this (both with NFSv3 and NFSv4) and failed. Also I
> > > > have looked through the code and I fail to see how this could happen. Is
> > > > this the only NFS mount that you have on your system? Didn't also the
> > > > WARN_ON in super_setup_bdi_name() trigger?
> > > >
> > > > Can you run with the attached debug patch and post full dmesg after the
> > > > failure?
> > > >
> > >
> > > Hello
> > >
> > > I forgot to said that I have 6 nfs mount point.
> > > mount -t nfs -o ro,tcp,hard,intr,async,vers=3 192.168.1.100:/usr/portage /usr/portage/
> > > mount -t nfs -o tcp,hard,intr,async,vers=3 192.168.1.100:/usr/local/portage /usr/local/portage/
> > > mount -t nfs -o tcp,hard,intr,async,vers=3 192.168.1.100:/mnt/tempo/portages/distfiles /usr/portage/distfiles
> > > mount -t nfs -o tcp,hard,intr,async,vers=4 192.168.1.100:/mnt/tempo/portages/cubiedev/packages /usr/portage/packages
> > > mount -t nfs -o tcp,hard,intr,async,vers=4,rsize=4096,wsize=4096 192.168.1.100:/var/tmp/portage/cubie /var/tmp/portage/
> > > mount -t nfs -o tcp,hard,intr,async,rsize=4096,wsize=4096 192.168.1.100:/mnt/tempo/cubie/local_kernel /usr/src/
> > >
> > > It's always the last which fail, but strangely inverting the two last
> > > made everything ok.
> >
> > Thanks for more info and the debug data. I still was not able to reproduce
> > the issue but after pondering my head on this for some time I have found a
> > bug in NFS conversion which can possibly cause the behavior you observe.
> > Does the attached patch fix the problem for you?
> >
> > If it does not, can you also post /proc/mounts and /etc/exports from you
> > NFS server?
> >
>
> This patch fix the issue

Thanks for testing! I'll send the fix to Jens, hopefully it will go in
still during this merge window.

Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR