[SRU][J/N:linux-bluefield][PATCH v1 0/1] mlxbf_pmc: lock warning for count_clock node

[David Thompson]

BugLink: https://bugs.launchpad.net/bugs/2127119

SRU Justification:

[Impact]
Booting BF3 with kernel that has lock-related debug enabled
will result in the following warning:

[ 10.231318] BUG: key ffff00008a3402a8 has not been registered!
[ 10.237249] ------------[ cut here ]------------
[ 10.241914] DEBUG_LOCKS_WARN_ON(1)
[ 10.241927] WARNING: CPU: 4 PID: 592 at kernel/locking/lockdep.c:4801 lockdep_init_map_type+0x1d4/0x2a0
[ 10.254700] Modules linked in: mlxbf_pmc(+) mlxbf_pka mlxbf_bootctl cppc_cpufreq(+) sch_fq_codel dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua drm ip_tables x_tables virtio_net crct10dif_ce ghash_ce sha2_ce net_failover sha256_arm64 failover sha1_ce nvme nvme_core vitesse gpio_mlxbf3 sdhci_of_dwcmshc sdhci_pltfm sdhci mlxbf_gige i2c_mlxbf pinctrl_mlxbf3 mlxbf_tmfifo pwr_mlxbf autofs4 aes_ce_blk crypto_simd cryptd aes_ce_cipher
[ 10.282360] mlxbf_gige MLNXBF17:00 oob_net0: renamed from eth0
[ 10.292917] CPU: 4 PID: 592 Comm: systemd-udevd Not tainted 5.15.189+ #2
[ 10.292922] Hardware name: https://www.mellandx.com BlueField-3 DPU/BlueField-3 DPU, BIOS 4.13.0.13780 Sep 30 2025
[ 10.292922] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 10.292925] pc : lockdep_init_map_type+0x1d4/0x2a0
[ 10.292931] lr : lockdep_init_map_type+0x1d4/0x2a0
[ 10.292932] sp : ffff8000096a3350
[ 10.292933] x29: ffff8000096a3350 x28: 00000000000001a4 x27: 00000000ffffee4b
[ 10.292937] x26: ffff00008a3402e0 x25: 0000000000000000 x24: 0000000000000000
[ 10.292939] x23: ffff00008a3402a8 x22: 0000000000000000 x21: ffffd1acf2833000
[ 10.292941] x20: ffff00008a3402a8 x19: ffff00008c10d378 x18: ffffd1acf1d3d000
[ 10.292944] x17: 000000007bba6d3c x16: ffffd1acef416114 x15: ffff0003dd914d88
[ 10.292946] x14: 0000000000000000 x13: 284e4f5f4e524157 x12: 5f534b434f4c5f47
[ 10.292949] x11: 656820747563205b x10: 0000000000000029 x9 : ffffd1acef49deb4
[ 10.292951] x8 : ffffd1acf0e93008 x7 : 0000000000000001 x6 : 0000000000000001
[ 10.385410] x5 : ffff8000096a31a0 x4 : ffff2e56eca7f000 x3 : ffff0003d20a5e80
[ 10.385412] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0003d20a5e80
[ 10.385415] Call trace:
[ OK ] Found device [ 10.385417] lockdep_init_map_type+0x1d4/0x2a0
/dev/ttyAMA0.[ 10.385423] __kernfs_create_file+0x84/0x140

[ 10.385428] sysfs_add_file_mode_ns+0xcc/0x1cc
[ 10.385431] internal_create_group+0x110/0x3d4
[ 10.385434] internal_create_groups.part.0+0x54/0xcc
[ 10.385436] sysfs_create_groups+0x24/0x40
[ 10.385438] device_add+0x6e8/0x93c
[ 10.444559] device_register+0x28/0x40
[ 10.448299] __hwmon_device_register+0x4b0/0x8a0
[ 10.452907] devm_hwmon_device_register_with_groups+0x7c/0xe0
[ 10.458641] mlxbf_pmc_probe+0x1e8/0x3e0 [mlxbf_pmc]
[ 10.463598] platform_probe+0x70/0x110
[ 10.467336] really_probe+0xd0/0x490
[ 10.470898] __driver_probe_device+0x148/0x190
[ 10.475333] driver_probe_device+0x48/0x180
[ 10.479506] __driver_attach+0x10c/0x250
[ 10.483414] bus_for_each_dev+0x7c/0xdc
[ 10.487242] driver_attach+0x2c/0x40
[ 10.487247] bus_add_driver+0x154/0x270
[ 10.487250] driver_register+0x80/0x13c
[ 10.487251] __platform_driver_register+0x30/0x40

[Fix]
The mlxbf_pmc driver should call "sysfs_attr_init()" during init
of data structures related to the "count_clock" sysfs node

[Test Case]
Build a custom kernel with the following two settings:
  CONFIG_PROVE_LOCKING=y
  CONFIG_LOCK_STAT=y
Boot this kernel on BF3
Verify that 'dmesg' output shows no lock-related warnings

[Regression Potential]
None, same technique used for other PMC driver sysfs nodes

David Thompson (1):
  UBUNTU: SAUCE: mlxbf_pmc: add sysfs_attr_init() during count_clock init

 drivers/platform/mellanox/mlxbf-pmc.c | 1 +
 1 file changed, 1 insertion(+)

-- 
2.43.2