On Wed, Mar 06, 2019 at 03:54:55PM -0800, john.hubbard@xxxxxxxxx wrote:
From: John Hubbard <jhubbard@xxxxxxxxxx>
Introduces put_user_page(), which simply calls put_page().
This provides a way to update all get_user_pages*() callers,
so that they call put_user_page(), instead of put_page().
So I've been running with these patches for a while but today while ramping up
my testing I hit the following:
[ 1355.557819] ------------[ cut here ]------------
[ 1355.563436] get_user_pages pin count overflowed
[ 1355.563446] WARNING: CPU: 1 PID: 1740 at mm/gup.c:73 get_gup_pin_page+0xa5/0xb0
[ 1355.577391] Modules linked in: ib_isert iscsi_target_mod ib_srpt target_core_mod ib_srp scsi_transpo
rt_srp ext4 mbcache jbd2 mlx4_ib opa_vnic rpcrdma sunrpc rdma_ucm ib_iser rdma_cm ib_umad iw_cm libiscs
i ib_ipoib scsi_transport_iscsi ib_cm sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm irqbyp
ass snd_hda_codec_realtek ib_uverbs snd_hda_codec_generic crct10dif_pclmul ledtrig_audio snd_hda_intel
crc32_pclmul snd_hda_codec snd_hda_core ghash_clmulni_intel snd_hwdep snd_pcm aesni_intel crypto_simd s
nd_timer ib_core cryptd snd glue_helper dax_pmem soundcore nd_pmem ipmi_si device_dax nd_btt ioatdma nd
_e820 ipmi_devintf ipmi_msghandler iTCO_wdt i2c_i801 iTCO_vendor_support libnvdimm pcspkr lpc_ich mei_m
e mei mfd_core wmi pcc_cpufreq acpi_cpufreq sch_fq_codel xfs libcrc32c mlx4_en sr_mod cdrom sd_mod mgag
200 drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops mlx4_core ttm crc32c_intel igb isci ah
ci dca libsas firewire_ohci drm i2c_algo_bit libahci scsi_transport_sas
[ 1355.577429] firewire_core crc_itu_t i2c_core libata dm_mod [last unloaded: rdmavt]
[ 1355.686703] CPU: 1 PID: 1740 Comm: reg-mr Not tainted 5.0.0+ #10
[ 1355.693851] Hardware name: Intel Corporation W2600CR/W2600CR, BIOS SE5C600.86B.02.04.0003.1023201411
38 10/23/2014
[ 1355.705750] RIP: 0010:get_gup_pin_page+0xa5/0xb0
[ 1355.711348] Code: e8 40 02 ff ff 80 3d ba a2 fb 00 00 b8 b5 ff ff ff 75 bb 48 c7 c7 48 0a e9 81 89 4
4 24 04 c6 05 a1 a2 fb 00 01 e8 35 63 e8 ff <0f> 0b 8b 44 24 04 eb 9c 0f 1f 00 66 66 66 66 90 41 57 49
bf 00 00
[ 1355.733244] RSP: 0018:ffffc90005a23b30 EFLAGS: 00010286
[ 1355.739536] RAX: 0000000000000000 RBX: ffffea0014220000 RCX: 0000000000000000
[ 1355.748005] RDX: 0000000000000003 RSI: ffffffff827d94a3 RDI: 0000000000000246
[ 1355.756453] RBP: ffffea0014220000 R08: 0000000000000002 R09: 0000000000022400
[ 1355.764907] R10: 0009ccf0ad0c4203 R11: 0000000000000001 R12: 0000000000010207
[ 1355.773369] R13: ffff8884130b7040 R14: fff0000000000fff R15: 000fffffffe00000
[ 1355.781836] FS: 00007f2680d0d740(0000) GS:ffff88842e840000(0000) knlGS:0000000000000000
[ 1355.791384] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1355.798319] CR2: 0000000000589000 CR3: 000000040b05e004 CR4: 00000000000606e0
[ 1355.806809] Call Trace:
[ 1355.810078] follow_page_pte+0x4f3/0x5c0
[ 1355.814987] __get_user_pages+0x1eb/0x730
[ 1355.820020] get_user_pages+0x3e/0x50
[ 1355.824657] ib_umem_get+0x283/0x500 [ib_uverbs]
[ 1355.830340] ? _cond_resched+0x15/0x30
[ 1355.835065] mlx4_ib_reg_user_mr+0x75/0x1e0 [mlx4_ib]
[ 1355.841235] ib_uverbs_reg_mr+0x10c/0x220 [ib_uverbs]
[ 1355.847400] ib_uverbs_write+0x2f9/0x4d0 [ib_uverbs]
[ 1355.853473] __vfs_write+0x36/0x1b0
[ 1355.857904] ? selinux_file_permission+0xf0/0x130
[ 1355.863702] ? security_file_permission+0x2e/0xe0
[ 1355.869503] vfs_write+0xa5/0x1a0
[ 1355.873751] ksys_write+0x4f/0xb0
[ 1355.878009] do_syscall_64+0x5b/0x180
[ 1355.882656] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1355.888862] RIP: 0033:0x7f2680ec3ed8
[ 1355.893420] Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 45 78 0
d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49
89 d4 55
[ 1355.915573] RSP: 002b:00007ffe65d50bc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 1355.924621] RAX: ffffffffffffffda RBX: 00007ffe65d50c74 RCX: 00007f2680ec3ed8
[ 1355.933195] RDX: 0000000000000030 RSI: 00007ffe65d50c80 RDI: 0000000000000003
[ 1355.941760] RBP: 0000000000000030 R08: 0000000000000007 R09: 0000000000581260
[ 1355.950326] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000581930
[ 1355.958885] R13: 000000000000000c R14: 0000000000581260 R15: 0000000000000000
[ 1355.967430] ---[ end trace bc771ac6189977a2 ]---
I'm not sure what I did to do this and I'm going to work on a reproducer. At
the time of the Warning I only had 1 GUP user?!?!?!?!
I'm not using ODP, so I don't think the changes we have discussed there are a
problem.
Ira