Subject: Re: [PATCH iwl-net v1] ice: fix bug with suspend and rebuild

From: Maciej Fijalkowski <[email-masked]>
Date: Wed, 6 Mar 2024 17:56:33 +0100

On Wed, Mar 06, 2024 at 05:46:02PM +0100, Maciej Fijalkowski wrote:
> On Mon, Mar 04, 2024 at 03:08:44PM -0800, Jesse Brandeburg wrote:
> > The ice driver would previously panic during suspend. This is caused
> > from the driver *only* calling the ice_vsi_free_q_vectors() function by
> > itself, when it is suspending. Since commit b3e7b3a6ee92 ("ice: prevent
> > NULL pointer deref during reload") the driver has zeroed out
> > num_q_vectors, and only restored it in ice_vsi_cfg_def().
> > 
> > This further causes the ice_rebuild() function to allocate a zero length
> > buffer, after which num_q_vectors is updated, and then the new value of
> > num_q_vectors is used to index into the zero length buffer, which
> > corrupts memory.
> > 
> > The fix entails making sure all the code referencing num_q_vectors only
> > does so after it has been reset via ice_vsi_cfg_def().
> > 
> > I didn't perform a full bisect, but I was able to test against 6.1.77
> > kernel and that ice driver works fine for suspend/resume with no panic,
> > so sometime since then, this problem was introduced.
> > 
> > Also clean up an un-needed init of a local variable in the function
> > being modified.
> > 
> > PANIC from 6.8.0-rc1:
> > 
> > [1026674.915596] PM: suspend exit
> > [1026675.664697] ice 0000:17:00.1: PTP reset successful
> > [1026675.664707] ice 0000:17:00.1: 2755 msecs passed between update to cached PHC time
> > [1026675.667660] ice 0000:b1:00.0: PTP reset successful
> > [1026675.675944] ice 0000:b1:00.0: 2832 msecs passed between update to cached PHC time
> > [1026677.137733] ixgbe 0000:31:00.0 ens787: NIC Link is Up 1 Gbps, Flow Control: None
> > [1026677.190201] BUG: kernel NULL pointer dereference, address: 0000000000000010
> > [1026677.192753] ice 0000:17:00.0: PTP reset successful
> > [1026677.192764] ice 0000:17:00.0: 4548 msecs passed between update to cached PHC time
> > [1026677.197928] #PF: supervisor read access in kernel mode
> > [1026677.197933] #PF: error_code(0x0000) - not-present page
> > [1026677.197937] PGD 1557a7067 P4D 0
> > [1026677.212133] ice 0000:b1:00.1: PTP reset successful
> > [1026677.212143] ice 0000:b1:00.1: 4344 msecs passed between update to cached PHC time
> > [1026677.212575]
> > [1026677.243142] Oops: 0000 [#1] PREEMPT SMP NOPTI
> > [1026677.247918] CPU: 23 PID: 42790 Comm: kworker/23:0 Kdump: loaded Tainted: G        W          6.8.0-rc1+ #1
> > [1026677.257989] Hardware name: Intel Corporation M50CYP2SBSTD/M50CYP2SBSTD, BIOS SE5C620.86B.01.01.0005.2202160810 02/16/2022
> > [1026677.269367] Workqueue: ice ice_service_task [ice]
> > [1026677.274592] RIP: 0010:ice_vsi_rebuild_set_coalesce+0x130/0x1e0 [ice]
> > [1026677.281421] Code: 0f 84 3a ff ff ff 41 0f b7 74 ec 02 66 89 b0 22 02 00 00 81 e6 ff 1f 00 00 e8 ec fd ff ff e9 35 ff ff ff 48 8b 43 30 49 63 ed <41> 0f b7 34 24 41 83 c5 01 48 8b 3c e8 66 89 b7 aa 02 00 00 81 e6
> > [1026677.300877] RSP: 0018:ff3be62a6399bcc0 EFLAGS: 00010202
> > [1026677.306556] RAX: ff28691e28980828 RBX: ff28691e41099828 RCX: 0000000000188000
> > [1026677.314148] RDX: 0000000000000000 RSI: 0000000000000010 RDI: ff28691e41099828
> > [1026677.321730] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> > [1026677.329311] R10: 0000000000000007 R11: ffffffffffffffc0 R12: 0000000000000010
> > [1026677.336896] R13: 0000000000000000 R14: 0000000000000000 R15: ff28691e0eaa81a0
> > [1026677.344472] FS:  0000000000000000(0000) GS:ff28693cbffc0000(0000) knlGS:0000000000000000
> > [1026677.353000] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [1026677.359195] CR2: 0000000000000010 CR3: 0000000128df4001 CR4: 0000000000771ef0
> > [1026677.366779] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > [1026677.374369] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > [1026677.381952] PKRU: 55555554
> > [1026677.385116] Call Trace:
> > [1026677.388023]  <TASK>
> > [1026677.390589]  ? __die+0x20/0x70
> > [1026677.394105]  ? page_fault_oops+0x82/0x160
> > [1026677.398576]  ? do_user_addr_fault+0x65/0x6a0
> > [1026677.403307]  ? exc_page_fault+0x6a/0x150
> > [1026677.407694]  ? asm_exc_page_fault+0x22/0x30
> > [1026677.412349]  ? ice_vsi_rebuild_set_coalesce+0x130/0x1e0 [ice]
> > [1026677.418614]  ice_vsi_rebuild+0x34b/0x3c0 [ice]
> > [1026677.423583]  ice_vsi_rebuild_by_type+0x76/0x180 [ice]
> > [1026677.429147]  ice_rebuild+0x18b/0x520 [ice]
> > [1026677.433746]  ? delay_tsc+0x8f/0xc0
> > [1026677.437630]  ice_do_reset+0xa3/0x190 [ice]
> > [1026677.442231]  ice_service_task+0x26/0x440 [ice]
> > [1026677.447180]  process_one_work+0x174/0x340
> > [1026677.451669]  worker_thread+0x27e/0x390
> > [1026677.455890]  ? __pfx_worker_thread+0x10/0x10
> > [1026677.460627]  kthread+0xee/0x120
> > [1026677.464235]  ? __pfx_kthread+0x10/0x10
> > [1026677.468445]  ret_from_fork+0x2d/0x50
> > [1026677.472476]  ? __pfx_kthread+0x10/0x10
> > [1026677.476671]  ret_from_fork_asm+0x1b/0x30
> > [1026677.481050]  </TASK>
> > 
> > Fixes: b3e7b3a6ee92 ("ice: prevent NULL pointer deref during reload")
> > Reported-by: Robert Elliott <[email-masked]>
> > Signed-off-by: Jesse Brandeburg <[email-masked]>
> 
> Reviewed-by: Maciej Fijalkowski <[email-masked]>
> 
> Well, that refactor of config path introduced lots of issues. Could
> validation folks include a short list of tests they tried out against
> tested patch?

Sorry, I got confused and now I saw the same thing Simon pointed out.

> 
> > ---
> >  drivers/net/ethernet/intel/ice/ice_lib.c | 16 ++++++++--------
> >  1 file changed, 8 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
> > index 097bf8fd6bf0..0f5a92a6b1e6 100644
> > --- a/drivers/net/ethernet/intel/ice/ice_lib.c
> > +++ b/drivers/net/ethernet/intel/ice/ice_lib.c
> > @@ -3238,7 +3238,7 @@ int ice_vsi_rebuild(struct ice_vsi *vsi, u32 vsi_flags)
> >  {
> >  	struct ice_vsi_cfg_params params = {};
> >  	struct ice_coalesce_stored *coalesce;

struct ice_coalesce_stored *coalesce __free(kfree);

?

and drop explicit kfree()s altogether?

> > -	int prev_num_q_vectors = 0;
> > +	int prev_num_q_vectors;
> >  	struct ice_pf *pf;
> >  	int ret;
> >  
> > @@ -3252,13 +3252,6 @@ int ice_vsi_rebuild(struct ice_vsi *vsi, u32 vsi_flags)
> >  	if (WARN_ON(vsi->type == ICE_VSI_VF && !vsi->vf))
> >  		return -EINVAL;
> >  
> > -	coalesce = kcalloc(vsi->num_q_vectors,
> > -			   sizeof(struct ice_coalesce_stored), GFP_KERNEL);
> > -	if (!coalesce)
> > -		return -ENOMEM;
> > -
> > -	prev_num_q_vectors = ice_vsi_rebuild_get_coalesce(vsi, coalesce);
> > -
> >  	ret = ice_vsi_realloc_stat_arrays(vsi);
> >  	if (ret)
> >  		goto err_vsi_cfg;
> > @@ -3268,6 +3261,13 @@ int ice_vsi_rebuild(struct ice_vsi *vsi, u32 vsi_flags)
> >  	if (ret)
> >  		goto err_vsi_cfg;
> >  
> > +	coalesce = kcalloc(vsi->num_q_vectors,
> > +			   sizeof(struct ice_coalesce_stored), GFP_KERNEL);
> > +	if (!coalesce)
> > +		return -ENOMEM;
> > +
> > +	prev_num_q_vectors = ice_vsi_rebuild_get_coalesce(vsi, coalesce);
> > +
> >  	ret = ice_vsi_cfg_tc_lan(pf, vsi);
> >  	if (ret) {
> >  		if (vsi_flags & ICE_VSI_FLAG_INIT) {
> > 
> > base-commit: 6923134fc6b62d7909169b3ad913ab72ee04233a
> > -- 
> > 2.39.3
> > 
> > 
>