Subject: Re: [PATCH net] ice: fix uninitialized dplls mutex usage

From: Maciej Fijalkowski <[email-masked]>
Date: Fri, 1 Mar 2024 15:38:39 +0100

On Fri, Mar 01, 2024 at 02:37:08PM +0100, Michal Schmidt wrote:
> The pf->dplls.lock mutex is initialized too late, after its first use.
> Move it to the top of ice_dpll_init.
> Note that the "err_exit" error path destroys the mutex. And the mutex is
> the last thing destroyed in ice_dpll_deinit.
> This fixes the following warning with CONFIG_DEBUG_MUTEXES:

Looks like ice_dpll_init_dpll() does dpll_device_register() and ops from
ice_dpll_ops can already acquire uninited mutex.

Reviewed-by: Maciej Fijalkowski <[email-masked]>

> 
>  ice 0000:10:00.0: The DDP package was successfully loaded: ICE OS Default Package version 1.3.36.0
>  ice 0000:10:00.0: 252.048 Gb/s available PCIe bandwidth (16.0 GT/s PCIe x16 link)
>  ice 0000:10:00.0: PTP init successful
>  ------------[ cut here ]------------
>  DEBUG_LOCKS_WARN_ON(lock->magic != lock)
>  WARNING: CPU: 0 PID: 410 at kernel/locking/mutex.c:587 __mutex_lock+0x773/0xd40
>  Modules linked in: crct10dif_pclmul crc32_pclmul crc32c_intel polyval_clmulni polyval_generic ice(+) nvme nvme_c>
>  CPU: 0 PID: 410 Comm: kworker/0:4 Not tainted 6.8.0-rc5+ #3
>  Hardware name: HPE ProLiant DL110 Gen10 Plus/ProLiant DL110 Gen10 Plus, BIOS U56 10/19/2023
>  Workqueue: events work_for_cpu_fn
>  RIP: 0010:__mutex_lock+0x773/0xd40
>  Code: c0 0f 84 1d f9 ff ff 44 8b 35 0d 9c 69 01 45 85 f6 0f 85 0d f9 ff ff 48 c7 c6 12 a2 a9 85 48 c7 c7 12 f1 a>
>  RSP: 0018:ff7eb1a3417a7ae0 EFLAGS: 00010286
>  RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
>  RDX: 0000000000000002 RSI: ffffffff85ac2bff RDI: 00000000ffffffff
>  RBP: ff7eb1a3417a7b80 R08: 0000000000000000 R09: 00000000ffffbfff
>  R10: ff7eb1a3417a7978 R11: ff32b80f7fd2e568 R12: 0000000000000000
>  R13: 0000000000000000 R14: 0000000000000000 R15: ff32b7f02c50e0d8
>  FS:  0000000000000000(0000) GS:ff32b80efe800000(0000) knlGS:0000000000000000
>  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>  CR2: 000055b5852cc000 CR3: 000000003c43a004 CR4: 0000000000771ef0
>  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>  PKRU: 55555554
>  Call Trace:
>   <TASK>
>   ? __warn+0x84/0x170
>   ? __mutex_lock+0x773/0xd40
>   ? report_bug+0x1c7/0x1d0
>   ? prb_read_valid+0x1b/0x30
>   ? handle_bug+0x42/0x70
>   ? exc_invalid_op+0x18/0x70
>   ? asm_exc_invalid_op+0x1a/0x20
>   ? __mutex_lock+0x773/0xd40
>   ? rcu_is_watching+0x11/0x50
>   ? __kmalloc_node_track_caller+0x346/0x490
>   ? ice_dpll_lock_status_get+0x28/0x50 [ice]
>   ? __pfx_ice_dpll_lock_status_get+0x10/0x10 [ice]
>   ? ice_dpll_lock_status_get+0x28/0x50 [ice]
>   ice_dpll_lock_status_get+0x28/0x50 [ice]
>   dpll_device_get_one+0x14f/0x2e0
>   dpll_device_event_send+0x7d/0x150
>   dpll_device_register+0x124/0x180
>   ice_dpll_init_dpll+0x7b/0xd0 [ice]
>   ice_dpll_init+0x224/0xa40 [ice]
>   ? _dev_info+0x70/0x90
>   ice_load+0x468/0x690 [ice]
>   ice_probe+0x75b/0xa10 [ice]
>   ? _raw_spin_unlock_irqrestore+0x4f/0x80
>   ? process_one_work+0x1a3/0x500
>   local_pci_probe+0x47/0xa0
>   work_for_cpu_fn+0x17/0x30
>   process_one_work+0x20d/0x500
>   worker_thread+0x1df/0x3e0
>   ? __pfx_worker_thread+0x10/0x10
>   kthread+0x103/0x140
>   ? __pfx_kthread+0x10/0x10
>   ret_from_fork+0x31/0x50
>   ? __pfx_kthread+0x10/0x10
>   ret_from_fork_asm+0x1b/0x30
>   </TASK>
>  irq event stamp: 125197
>  hardirqs last  enabled at (125197): [<ffffffff8416409d>] finish_task_switch.isra.0+0x12d/0x3d0
>  hardirqs last disabled at (125196): [<ffffffff85134044>] __schedule+0xea4/0x19f0
>  softirqs last  enabled at (105334): [<ffffffff84e1e65a>] napi_get_frags_check+0x1a/0x60
>  softirqs last disabled at (105332): [<ffffffff84e1e65a>] napi_get_frags_check+0x1a/0x60
>  ---[ end trace 0000000000000000 ]---
> 
> Fixes: d7999f5ea64b ("ice: implement dpll interface to control cgu")
> Signed-off-by: Michal Schmidt <[email-masked]>
> ---
>  drivers/net/ethernet/intel/ice/ice_dpll.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_dpll.c b/drivers/net/ethernet/intel/ice/ice_dpll.c
> index adfa1f2a80a6..fda9140c0da4 100644
> --- a/drivers/net/ethernet/intel/ice/ice_dpll.c
> +++ b/drivers/net/ethernet/intel/ice/ice_dpll.c
> @@ -2120,6 +2120,7 @@ void ice_dpll_init(struct ice_pf *pf)
>  	struct ice_dplls *d = &pf->dplls;
>  	int err = 0;
>  
> +	mutex_init(&d->lock);
>  	err = ice_dpll_init_info(pf, cgu);
>  	if (err)
>  		goto err_exit;
> @@ -2132,7 +2133,6 @@ void ice_dpll_init(struct ice_pf *pf)
>  	err = ice_dpll_init_pins(pf, cgu);
>  	if (err)
>  		goto deinit_pps;
> -	mutex_init(&d->lock);
>  	if (cgu) {
>  		err = ice_dpll_init_worker(pf);
>  		if (err)
> -- 
> 2.43.2
> 
>