2021-03-03 14:52:49

by Zhi Li

[permalink] [raw]
Subject: [PATCH 1/1] mmc: cqhci: fix random crash when remove mmc module

[ 6684.493350] Unable to handle kernel paging request at virtual address ffff800011c5b0f0
[ 6684.498531] mmc0: card 0001 removed
[ 6684.501556] Mem abort info:
[ 6684.509681] ESR = 0x96000047
[ 6684.512786] EC = 0x25: DABT (current EL), IL = 32 bits
[ 6684.518394] SET = 0, FnV = 0
[ 6684.521707] EA = 0, S1PTW = 0
[ 6684.524998] Data abort info:
[ 6684.528236] ISV = 0, ISS = 0x00000047
[ 6684.532986] CM = 0, WnR = 1
[ 6684.536129] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000081b22000
[ 6684.543923] [ffff800011c5b0f0] pgd=00000000bffff003, p4d=00000000bffff003, pud=00000000bfffe003, pmd=00000000900e1003, pte=0000000000000000
[ 6684.557915] Internal error: Oops: 96000047 [#1] PREEMPT SMP
[ 6684.564240] Modules linked in: sdhci_esdhc_imx(-) sdhci_pltfm sdhci cqhci mmc_block mmc_core fsl_jr_uio caam_jr caamkeyblob_desc caamhash_desc caamalg_desc crypto_engine rng_core authenc libdes crct10dif_ce flexcan can_dev caam error [last unloaded: mmc_core]
[ 6684.587281] CPU: 0 PID: 79138 Comm: kworker/0:3H Not tainted 5.10.9-01410-g3ba33182767b-dirty #10
[ 6684.596160] Hardware name: Freescale i.MX8DXL EVK (DT)
[ 6684.601320] Workqueue: kblockd blk_mq_run_work_fn

[ 6684.606094] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
[ 6684.612286] pc : cqhci_request+0x148/0x4e8 [cqhci]
^GMessage from syslogd@ at Thu Jan 1 01:51:24 1970 ...[ 6684.617085] lr : cqhci_request+0x314/0x4e8 [cqhci]
[ 6684.626734] sp : ffff80001243b9f0
[ 6684.630049] x29: ffff80001243b9f0 x28: ffff00002c3dd000
[ 6684.635367] x27: 0000000000000001 x26: 0000000000000001
[ 6684.640690] x25: ffff00002c451000 x24: 000000000000000f
[ 6684.646007] x23: ffff000017e71c80 x22: ffff00002c451000
[ 6684.651326] x21: ffff00002c0f3550 x20: ffff00002c0f3550
[ 6684.656651] x19: ffff000017d46880 x18: ffff00002cea1500
[ 6684.661977] x17: 0000000000000000 x16: 0000000000000000
[ 6684.667294] x15: 000001ee628e3ed1 x14: 0000000000000278
[ 6684.672610] x13: 0000000000000001 x12: 0000000000000001
[ 6684.677927] x11: 0000000000000000 x10: 0000000000000000
[ 6684.683243] x9 : 000000000000002b x8 : 0000000000001000
[ 6684.688560] x7 : 0000000000000010 x6 : ffff00002c0f3678
[ 6684.693886] x5 : 000000000000000f x4 : ffff800011c5b000
[ 6684.699211] x3 : 000000000002d988 x2 : 0000000000000008
[ 6684.704537] x1 : 00000000000000f0 x0 : 0002d9880008102f
[ 6684.709854] Call trace:
[ 6684.712313] cqhci_request+0x148/0x4e8 [cqhci]
[ 6684.716803] mmc_cqe_start_req+0x58/0x68 [mmc_core]
[ 6684.721698] mmc_blk_mq_issue_rq+0x460/0x810 [mmc_block]
[ 6684.727018] mmc_mq_queue_rq+0x118/0x2b0 [mmc_block]

cqhci_request was called after cqhci_disable.

cqhci_disable cqhci_request
{ {
dmam_free_coherent(); (1) free
if(!cq_host->enable)
return
(2) pass check here
cq_host->enable = false;

task_desc= get_desc(cq_host,tag);
^^^^ crash here
(3) access memory which is already free

} }

Signed-off-by: Frank Li <[email protected]>
---
drivers/mmc/host/cqhci-core.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/cqhci-core.c b/drivers/mmc/host/cqhci-core.c
index 93b0432bb601..36d292261e50 100644
--- a/drivers/mmc/host/cqhci-core.c
+++ b/drivers/mmc/host/cqhci-core.c
@@ -389,6 +389,7 @@ static void cqhci_off(struct mmc_host *mmc)
static void cqhci_disable(struct mmc_host *mmc)
{
struct cqhci_host *cq_host = mmc->cqe_private;
+ unsigned long flags;

if (!cq_host->enabled)
return;
@@ -397,6 +398,11 @@ static void cqhci_disable(struct mmc_host *mmc)

__cqhci_disable(cq_host);

+ /* need wait for cqhci_request finish before free memory */
+ spin_lock_irqsave(&cq_host->lock, flags);
+ cq_host->enabled = false;
+ spin_unlock_irqrestore(&cq_host->lock, flags);
+
dmam_free_coherent(mmc_dev(mmc), cq_host->data_size,
cq_host->trans_desc_base,
cq_host->trans_desc_dma_base);
@@ -408,7 +414,6 @@ static void cqhci_disable(struct mmc_host *mmc)
cq_host->trans_desc_base = NULL;
cq_host->desc_base = NULL;

- cq_host->enabled = false;
}

static void cqhci_prep_task_desc(struct mmc_request *mrq,
@@ -612,6 +617,13 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
cq_host->ops->enable(mmc);
}

+ spin_lock_irqsave(&cq_host->lock, flags);
+ if (!cq_host->enabled) {
+ pr_err("%s: cqhci: not enabled\n", mmc_hostname(mmc));
+ err = -EINVAL;
+ goto out_unlock;
+ }
+
if (mrq->data) {
cqhci_prep_task_desc(mrq, cq_host, tag);

@@ -619,14 +631,12 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
if (err) {
pr_err("%s: cqhci: failed to setup tx desc: %d\n",
mmc_hostname(mmc), err);
- return err;
+ goto out_unlock;
}
} else {
cqhci_prep_dcmd_desc(mmc, mrq);
}

- spin_lock_irqsave(&cq_host->lock, flags);
-
if (cq_host->recovery_halt) {
err = -EBUSY;
goto out_unlock;
--
2.25.1


2021-03-04 05:56:58

by Adrian Hunter

[permalink] [raw]
Subject: Re: [PATCH 1/1] mmc: cqhci: fix random crash when remove mmc module

On 1/03/21 7:21 pm, Frank Li wrote:
> [ 6684.493350] Unable to handle kernel paging request at virtual address ffff800011c5b0f0
> [ 6684.498531] mmc0: card 0001 removed
> [ 6684.501556] Mem abort info:
> [ 6684.509681] ESR = 0x96000047
> [ 6684.512786] EC = 0x25: DABT (current EL), IL = 32 bits
> [ 6684.518394] SET = 0, FnV = 0
> [ 6684.521707] EA = 0, S1PTW = 0
> [ 6684.524998] Data abort info:
> [ 6684.528236] ISV = 0, ISS = 0x00000047
> [ 6684.532986] CM = 0, WnR = 1
> [ 6684.536129] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000081b22000
> [ 6684.543923] [ffff800011c5b0f0] pgd=00000000bffff003, p4d=00000000bffff003, pud=00000000bfffe003, pmd=00000000900e1003, pte=0000000000000000
> [ 6684.557915] Internal error: Oops: 96000047 [#1] PREEMPT SMP
> [ 6684.564240] Modules linked in: sdhci_esdhc_imx(-) sdhci_pltfm sdhci cqhci mmc_block mmc_core fsl_jr_uio caam_jr caamkeyblob_desc caamhash_desc caamalg_desc crypto_engine rng_core authenc libdes crct10dif_ce flexcan can_dev caam error [last unloaded: mmc_core]
> [ 6684.587281] CPU: 0 PID: 79138 Comm: kworker/0:3H Not tainted 5.10.9-01410-g3ba33182767b-dirty #10
> [ 6684.596160] Hardware name: Freescale i.MX8DXL EVK (DT)
> [ 6684.601320] Workqueue: kblockd blk_mq_run_work_fn
>
> [ 6684.606094] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
> [ 6684.612286] pc : cqhci_request+0x148/0x4e8 [cqhci]
> ^GMessage from syslogd@ at Thu Jan 1 01:51:24 1970 ...[ 6684.617085] lr : cqhci_request+0x314/0x4e8 [cqhci]
> [ 6684.626734] sp : ffff80001243b9f0
> [ 6684.630049] x29: ffff80001243b9f0 x28: ffff00002c3dd000
> [ 6684.635367] x27: 0000000000000001 x26: 0000000000000001
> [ 6684.640690] x25: ffff00002c451000 x24: 000000000000000f
> [ 6684.646007] x23: ffff000017e71c80 x22: ffff00002c451000
> [ 6684.651326] x21: ffff00002c0f3550 x20: ffff00002c0f3550
> [ 6684.656651] x19: ffff000017d46880 x18: ffff00002cea1500
> [ 6684.661977] x17: 0000000000000000 x16: 0000000000000000
> [ 6684.667294] x15: 000001ee628e3ed1 x14: 0000000000000278
> [ 6684.672610] x13: 0000000000000001 x12: 0000000000000001
> [ 6684.677927] x11: 0000000000000000 x10: 0000000000000000
> [ 6684.683243] x9 : 000000000000002b x8 : 0000000000001000
> [ 6684.688560] x7 : 0000000000000010 x6 : ffff00002c0f3678
> [ 6684.693886] x5 : 000000000000000f x4 : ffff800011c5b000
> [ 6684.699211] x3 : 000000000002d988 x2 : 0000000000000008
> [ 6684.704537] x1 : 00000000000000f0 x0 : 0002d9880008102f
> [ 6684.709854] Call trace:
> [ 6684.712313] cqhci_request+0x148/0x4e8 [cqhci]
> [ 6684.716803] mmc_cqe_start_req+0x58/0x68 [mmc_core]
> [ 6684.721698] mmc_blk_mq_issue_rq+0x460/0x810 [mmc_block]
> [ 6684.727018] mmc_mq_queue_rq+0x118/0x2b0 [mmc_block]
>
> cqhci_request was called after cqhci_disable.
>
> cqhci_disable cqhci_request
> { {
> dmam_free_coherent(); (1) free
> if(!cq_host->enable)
> return
> (2) pass check here
> cq_host->enable = false;
>
> task_desc= get_desc(cq_host,tag);
> ^^^^ crash here
> (3) access memory which is already free
>
> } }
>
> Signed-off-by: Frank Li <[email protected]>
> ---
> drivers/mmc/host/cqhci-core.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/host/cqhci-core.c b/drivers/mmc/host/cqhci-core.c
> index 93b0432bb601..36d292261e50 100644
> --- a/drivers/mmc/host/cqhci-core.c
> +++ b/drivers/mmc/host/cqhci-core.c
> @@ -389,6 +389,7 @@ static void cqhci_off(struct mmc_host *mmc)
> static void cqhci_disable(struct mmc_host *mmc)
> {
> struct cqhci_host *cq_host = mmc->cqe_private;
> + unsigned long flags;
>
> if (!cq_host->enabled)
> return;
> @@ -397,6 +398,11 @@ static void cqhci_disable(struct mmc_host *mmc)
>
> __cqhci_disable(cq_host);
>
> + /* need wait for cqhci_request finish before free memory */
> + spin_lock_irqsave(&cq_host->lock, flags);
> + cq_host->enabled = false;
> + spin_unlock_irqrestore(&cq_host->lock, flags);
> +
> dmam_free_coherent(mmc_dev(mmc), cq_host->data_size,
> cq_host->trans_desc_base,
> cq_host->trans_desc_dma_base);
> @@ -408,7 +414,6 @@ static void cqhci_disable(struct mmc_host *mmc)
> cq_host->trans_desc_base = NULL;
> cq_host->desc_base = NULL;
>
> - cq_host->enabled = false;
> }
>
> static void cqhci_prep_task_desc(struct mmc_request *mrq,
> @@ -612,6 +617,13 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
> cq_host->ops->enable(mmc);
> }
>
> + spin_lock_irqsave(&cq_host->lock, flags);
> + if (!cq_host->enabled) {
> + pr_err("%s: cqhci: not enabled\n", mmc_hostname(mmc));
> + err = -EINVAL;
> + goto out_unlock;
> + }
> +
> if (mrq->data) {
> cqhci_prep_task_desc(mrq, cq_host, tag);
>
> @@ -619,14 +631,12 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
> if (err) {
> pr_err("%s: cqhci: failed to setup tx desc: %d\n",
> mmc_hostname(mmc), err);
> - return err;
> + goto out_unlock;
> }
> } else {
> cqhci_prep_dcmd_desc(mmc, mrq);
> }
>
> - spin_lock_irqsave(&cq_host->lock, flags);
> -
> if (cq_host->recovery_halt) {
> err = -EBUSY;
> goto out_unlock;
>

Please try the following instead:


diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
index c2e70b757dd1..dfc8d2877115 100644
--- a/drivers/mmc/core/bus.c
+++ b/drivers/mmc/core/bus.c
@@ -399,11 +399,6 @@ void mmc_remove_card(struct mmc_card *card)
mmc_remove_card_debugfs(card);
#endif

- if (host->cqe_enabled) {
- host->cqe_ops->cqe_disable(host);
- host->cqe_enabled = false;
- }
-
if (mmc_card_present(card)) {
if (mmc_host_is_spi(card->host)) {
pr_info("%s: SPI card removed\n",
@@ -416,6 +411,11 @@ void mmc_remove_card(struct mmc_card *card)
of_node_put(card->dev.of_node);
}

+ if (host->cqe_enabled) {
+ host->cqe_ops->cqe_disable(host);
+ host->cqe_enabled = false;
+ }
+
put_device(&card->dev);
}


2021-03-04 06:37:21

by Adrian Hunter

[permalink] [raw]
Subject: Re: [PATCH 1/1] mmc: cqhci: fix random crash when remove mmc module

On 2/03/21 5:12 pm, Zhi Li wrote:
>
>
> On Tue, Mar 2, 2021 at 1:03 AM Adrian Hunter <[email protected] <mailto:[email protected]>> wrote:
>
> On 1/03/21 7:21 pm, Frank Li wrote:
> > [ 6684.493350] Unable to handle kernel paging request at virtual address ffff800011c5b0f0
> > [ 6684.498531] mmc0: card 0001 removed
> > [ 6684.501556] Mem abort info:
> > [ 6684.509681]   ESR = 0x96000047
> > [ 6684.512786]   EC = 0x25: DABT (current EL), IL = 32 bits
> > [ 6684.518394]   SET = 0, FnV = 0
> > [ 6684.521707]   EA = 0, S1PTW = 0
> > [ 6684.524998] Data abort info:
> > [ 6684.528236]   ISV = 0, ISS = 0x00000047
> > [ 6684.532986]   CM = 0, WnR = 1
> > [ 6684.536129] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000081b22000
> > [ 6684.543923] [ffff800011c5b0f0] pgd=00000000bffff003, p4d=00000000bffff003, pud=00000000bfffe003, pmd=00000000900e1003, pte=0000000000000000
> > [ 6684.557915] Internal error: Oops: 96000047 [#1] PREEMPT SMP
> > [ 6684.564240] Modules linked in: sdhci_esdhc_imx(-) sdhci_pltfm sdhci cqhci mmc_block mmc_core fsl_jr_uio caam_jr caamkeyblob_desc caamhash_desc caamalg_desc crypto_engine rng_core authenc libdes crct10dif_ce flexcan can_dev caam error [last unloaded: mmc_core]
> > [ 6684.587281] CPU: 0 PID: 79138 Comm: kworker/0:3H Not tainted 5.10.9-01410-g3ba33182767b-dirty #10
> > [ 6684.596160] Hardware name: Freescale i.MX8DXL EVK (DT)
> > [ 6684.601320] Workqueue: kblockd blk_mq_run_work_fn
> >
> > [ 6684.606094] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
> > [ 6684.612286] pc : cqhci_request+0x148/0x4e8 [cqhci]
> > ^GMessage from syslogd@  at Thu Jan  1 01:51:24 1970 ...[ 6684.617085] lr : cqhci_request+0x314/0x4e8 [cqhci]
> > [ 6684.626734] sp : ffff80001243b9f0
> > [ 6684.630049] x29: ffff80001243b9f0 x28: ffff00002c3dd000
> > [ 6684.635367] x27: 0000000000000001 x26: 0000000000000001
> > [ 6684.640690] x25: ffff00002c451000 x24: 000000000000000f
> > [ 6684.646007] x23: ffff000017e71c80 x22: ffff00002c451000
> > [ 6684.651326] x21: ffff00002c0f3550 x20: ffff00002c0f3550
> > [ 6684.656651] x19: ffff000017d46880 x18: ffff00002cea1500
> > [ 6684.661977] x17: 0000000000000000 x16: 0000000000000000
> > [ 6684.667294] x15: 000001ee628e3ed1 x14: 0000000000000278
> > [ 6684.672610] x13: 0000000000000001 x12: 0000000000000001
> > [ 6684.677927] x11: 0000000000000000 x10: 0000000000000000
> > [ 6684.683243] x9 : 000000000000002b x8 : 0000000000001000
> > [ 6684.688560] x7 : 0000000000000010 x6 : ffff00002c0f3678
> > [ 6684.693886] x5 : 000000000000000f x4 : ffff800011c5b000
> > [ 6684.699211] x3 : 000000000002d988 x2 : 0000000000000008
> > [ 6684.704537] x1 : 00000000000000f0 x0 : 0002d9880008102f
> > [ 6684.709854] Call trace:
> > [ 6684.712313]  cqhci_request+0x148/0x4e8 [cqhci]
> > [ 6684.716803]  mmc_cqe_start_req+0x58/0x68 [mmc_core]
> > [ 6684.721698]  mmc_blk_mq_issue_rq+0x460/0x810 [mmc_block]
> > [ 6684.727018]  mmc_mq_queue_rq+0x118/0x2b0 [mmc_block]
> >
> > cqhci_request was called after cqhci_disable.
> >
> > cqhci_disable                                 cqhci_request
> > {                                             {
> >       dmam_free_coherent();  (1) free
> >                                                   if(!cq_host->enable)
> >                                                        return
> >                                        (2) pass check here
> >       cq_host->enable = false;
> >
> >                                                   task_desc= get_desc(cq_host,tag);
> >                                                              ^^^^ crash here
> >                                          (3) access memory which is already free
> >
> > }                                             }
> >
> > Signed-off-by: Frank Li <[email protected] <mailto:[email protected]>>
> > ---
> >  drivers/mmc/host/cqhci-core.c | 18 ++++++++++++++----
> >  1 file changed, 14 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/mmc/host/cqhci-core.c b/drivers/mmc/host/cqhci-core.c
> > index 93b0432bb601..36d292261e50 100644
> > --- a/drivers/mmc/host/cqhci-core.c
> > +++ b/drivers/mmc/host/cqhci-core.c
> > @@ -389,6 +389,7 @@ static void cqhci_off(struct mmc_host *mmc)
> >  static void cqhci_disable(struct mmc_host *mmc)
> >  {
> >       struct cqhci_host *cq_host = mmc->cqe_private;
> > +     unsigned long flags;
> > 
> >       if (!cq_host->enabled)
> >               return;
> > @@ -397,6 +398,11 @@ static void cqhci_disable(struct mmc_host *mmc)
> > 
> >       __cqhci_disable(cq_host);
> > 
> > +     /* need wait for cqhci_request finish before free memory */
> > +     spin_lock_irqsave(&cq_host->lock, flags);
> > +     cq_host->enabled = false;
> > +     spin_unlock_irqrestore(&cq_host->lock, flags);
> > +
> >       dmam_free_coherent(mmc_dev(mmc), cq_host->data_size,
> >                          cq_host->trans_desc_base,
> >                          cq_host->trans_desc_dma_base);
> > @@ -408,7 +414,6 @@ static void cqhci_disable(struct mmc_host *mmc)
> >       cq_host->trans_desc_base = NULL;
> >       cq_host->desc_base = NULL;
> > 
> > -     cq_host->enabled = false;
> >  }
> > 
> >  static void cqhci_prep_task_desc(struct mmc_request *mrq,
> > @@ -612,6 +617,13 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
> >                       cq_host->ops->enable(mmc);
> >       }
> > 
> > +     spin_lock_irqsave(&cq_host->lock, flags);
> > +     if (!cq_host->enabled) {
> > +             pr_err("%s: cqhci: not enabled\n", mmc_hostname(mmc));
> > +             err = -EINVAL;
> > +             goto out_unlock;
> > +     }
> > +
> >       if (mrq->data) {
> >               cqhci_prep_task_desc(mrq, cq_host, tag);
> > 
> > @@ -619,14 +631,12 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
> >               if (err) {
> >                       pr_err("%s: cqhci: failed to setup tx desc: %d\n",
> >                              mmc_hostname(mmc), err);
> > -                     return err;
> > +                     goto out_unlock;
> >               }
> >       } else {
> >               cqhci_prep_dcmd_desc(mmc, mrq);
> >       }
> > 
> > -     spin_lock_irqsave(&cq_host->lock, flags);
> > -
> >       if (cq_host->recovery_halt) {
> >               err = -EBUSY;
> >               goto out_unlock;
> >
>
> Please try the following instead:
>
>
> diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
> index c2e70b757dd1..dfc8d2877115 100644
> --- a/drivers/mmc/core/bus.c
> +++ b/drivers/mmc/core/bus.c
> @@ -399,11 +399,6 @@ void mmc_remove_card(struct mmc_card *card)
>         mmc_remove_card_debugfs(card);
>  #endif
>
> -       if (host->cqe_enabled) {
> -               host->cqe_ops->cqe_disable(host);
> -               host->cqe_enabled = false;
> -       }
> -
>         if (mmc_card_present(card)) {
>                 if (mmc_host_is_spi(card->host)) {
>                         pr_info("%s: SPI card removed\n",
> @@ -416,6 +411,11 @@ void mmc_remove_card(struct mmc_card *card)
>                 of_node_put(card->dev.of_node);
>         }
>
> +       if (host->cqe_enabled) {
> +               host->cqe_ops->cqe_disable(host);
> +               host->cqe_enabled = false;
> +       }
> +
>         put_device(&card->dev);
>  }
>
>
> Actually this is my first solution,  it can't resolve issues 100% and just reduce possibility. 
>
> One core run                                                                          The another core run
> mmc_remove_card                                                                mmc_mq_queue_rq
> {                                                                                              {
>                                                                
>                                                                                                              if (mmc_card_removed(mq->card)) {
>                                                                                                                               req->rq_flags |= RQF_QUIET; 
>                                                                                                                                return BLK_STS_IOERR;
>                                                                                                               }
>                                                                                                               //pass check here
>         device_del(&card->dev);

Deleting the card device removes it from the block driver
(i.e. mmc_blk_remove()), which cleans up the request queues,
so the scenario you describe here should never happen.

Can you determine if mmc_blk_remove() is called and whether
it cleans up blk queues?


>         //free resource here
>         host->cqe_ops->cqe_disable(host);  
>        
>                                                                                                               call  cqhci_request
>                                                                                                                 //kernel dump here to access memory that is already free. 
>
> }                                                                                               }
>  
> There is one fundamental problem that there is NOT read lock when checking mmc_card_removed, and write lock for updating md->card.  
> The risk conditions always exist between queue request and card remove. 
>
> There are no issues for non-command queue host controllers, it just causes a redundant cmd sent by host,  cmd will be timeout.  Just an expected IO error 
> happened. Maybe just errors code is different.  
>
> But Cmd queue is different,  cmd queue disabled  function free memory resources. if risk conditions happen, there are kernel dump.     
>
>  
>

2021-03-04 12:19:21

by Zhi Li

[permalink] [raw]
Subject: Re: [PATCH 1/1] mmc: cqhci: fix random crash when remove mmc module

On Tue, Mar 2, 2021 at 12:39 PM Zhi Li <[email protected]> wrote:
>
> On Tue, Mar 2, 2021 at 10:25 AM Adrian Hunter <[email protected]> wrote:
> >
> > On 2/03/21 5:12 pm, Zhi Li wrote:
> > >
> > >
> > > On Tue, Mar 2, 2021 at 1:03 AM Adrian Hunter <[email protected] <mailto:[email protected]>> wrote:
> > >
> > > On 1/03/21 7:21 pm, Frank Li wrote:
> > > > [ 6684.493350] Unable to handle kernel paging request at virtual address ffff800011c5b0f0
> > > > [ 6684.498531] mmc0: card 0001 removed
> > > > [ 6684.501556] Mem abort info:
> > > > [ 6684.509681] ESR = 0x96000047
> > > > [ 6684.512786] EC = 0x25: DABT (current EL), IL = 32 bits
> > > > [ 6684.518394] SET = 0, FnV = 0
> > > > [ 6684.521707] EA = 0, S1PTW = 0
> > > > [ 6684.524998] Data abort info:
> > > > [ 6684.528236] ISV = 0, ISS = 0x00000047
> > > > [ 6684.532986] CM = 0, WnR = 1
> > > > [ 6684.536129] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000081b22000
> > > > [ 6684.543923] [ffff800011c5b0f0] pgd=00000000bffff003, p4d=00000000bffff003, pud=00000000bfffe003, pmd=00000000900e1003, pte=0000000000000000
> > > > [ 6684.557915] Internal error: Oops: 96000047 [#1] PREEMPT SMP
> > > > [ 6684.564240] Modules linked in: sdhci_esdhc_imx(-) sdhci_pltfm sdhci cqhci mmc_block mmc_core fsl_jr_uio caam_jr caamkeyblob_desc caamhash_desc caamalg_desc crypto_engine rng_core authenc libdes crct10dif_ce flexcan can_dev caam error [last unloaded: mmc_core]
> > > > [ 6684.587281] CPU: 0 PID: 79138 Comm: kworker/0:3H Not tainted 5.10.9-01410-g3ba33182767b-dirty #10
> > > > [ 6684.596160] Hardware name: Freescale i.MX8DXL EVK (DT)
> > > > [ 6684.601320] Workqueue: kblockd blk_mq_run_work_fn
> > > >
> > > > [ 6684.606094] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
> > > > [ 6684.612286] pc : cqhci_request+0x148/0x4e8 [cqhci]
> > > > ^GMessage from syslogd@ at Thu Jan 1 01:51:24 1970 ...[ 6684.617085] lr : cqhci_request+0x314/0x4e8 [cqhci]
> > > > [ 6684.626734] sp : ffff80001243b9f0
> > > > [ 6684.630049] x29: ffff80001243b9f0 x28: ffff00002c3dd000
> > > > [ 6684.635367] x27: 0000000000000001 x26: 0000000000000001
> > > > [ 6684.640690] x25: ffff00002c451000 x24: 000000000000000f
> > > > [ 6684.646007] x23: ffff000017e71c80 x22: ffff00002c451000
> > > > [ 6684.651326] x21: ffff00002c0f3550 x20: ffff00002c0f3550
> > > > [ 6684.656651] x19: ffff000017d46880 x18: ffff00002cea1500
> > > > [ 6684.661977] x17: 0000000000000000 x16: 0000000000000000
> > > > [ 6684.667294] x15: 000001ee628e3ed1 x14: 0000000000000278
> > > > [ 6684.672610] x13: 0000000000000001 x12: 0000000000000001
> > > > [ 6684.677927] x11: 0000000000000000 x10: 0000000000000000
> > > > [ 6684.683243] x9 : 000000000000002b x8 : 0000000000001000
> > > > [ 6684.688560] x7 : 0000000000000010 x6 : ffff00002c0f3678
> > > > [ 6684.693886] x5 : 000000000000000f x4 : ffff800011c5b000
> > > > [ 6684.699211] x3 : 000000000002d988 x2 : 0000000000000008
> > > > [ 6684.704537] x1 : 00000000000000f0 x0 : 0002d9880008102f
> > > > [ 6684.709854] Call trace:
> > > > [ 6684.712313] cqhci_request+0x148/0x4e8 [cqhci]
> > > > [ 6684.716803] mmc_cqe_start_req+0x58/0x68 [mmc_core]
> > > > [ 6684.721698] mmc_blk_mq_issue_rq+0x460/0x810 [mmc_block]
> > > > [ 6684.727018] mmc_mq_queue_rq+0x118/0x2b0 [mmc_block]
> > > >
> > > > cqhci_request was called after cqhci_disable.
> > > >
> > > > cqhci_disable cqhci_request
> > > > { {
> > > > dmam_free_coherent(); (1) free
> > > > if(!cq_host->enable)
> > > > return
> > > > (2) pass check here
> > > > cq_host->enable = false;
> > > >
> > > > task_desc= get_desc(cq_host,tag);
> > > > ^^^^ crash here
> > > > (3) access memory which is already free
> > > >
> > > > } }
> > > >
> > > > Signed-off-by: Frank Li <[email protected] <mailto:[email protected]>>
> > > > ---
> > > > drivers/mmc/host/cqhci-core.c | 18 ++++++++++++++----
> > > > 1 file changed, 14 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/mmc/host/cqhci-core.c b/drivers/mmc/host/cqhci-core.c
> > > > index 93b0432bb601..36d292261e50 100644
> > > > --- a/drivers/mmc/host/cqhci-core.c
> > > > +++ b/drivers/mmc/host/cqhci-core.c
> > > > @@ -389,6 +389,7 @@ static void cqhci_off(struct mmc_host *mmc)
> > > > static void cqhci_disable(struct mmc_host *mmc)
> > > > {
> > > > struct cqhci_host *cq_host = mmc->cqe_private;
> > > > + unsigned long flags;
> > > >
> > > > if (!cq_host->enabled)
> > > > return;
> > > > @@ -397,6 +398,11 @@ static void cqhci_disable(struct mmc_host *mmc)
> > > >
> > > > __cqhci_disable(cq_host);
> > > >
> > > > + /* need wait for cqhci_request finish before free memory */
> > > > + spin_lock_irqsave(&cq_host->lock, flags);
> > > > + cq_host->enabled = false;
> > > > + spin_unlock_irqrestore(&cq_host->lock, flags);
> > > > +
> > > > dmam_free_coherent(mmc_dev(mmc), cq_host->data_size,
> > > > cq_host->trans_desc_base,
> > > > cq_host->trans_desc_dma_base);
> > > > @@ -408,7 +414,6 @@ static void cqhci_disable(struct mmc_host *mmc)
> > > > cq_host->trans_desc_base = NULL;
> > > > cq_host->desc_base = NULL;
> > > >
> > > > - cq_host->enabled = false;
> > > > }
> > > >
> > > > static void cqhci_prep_task_desc(struct mmc_request *mrq,
> > > > @@ -612,6 +617,13 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
> > > > cq_host->ops->enable(mmc);
> > > > }
> > > >
> > > > + spin_lock_irqsave(&cq_host->lock, flags);
> > > > + if (!cq_host->enabled) {
> > > > + pr_err("%s: cqhci: not enabled\n", mmc_hostname(mmc));
> > > > + err = -EINVAL;
> > > > + goto out_unlock;
> > > > + }
> > > > +
> > > > if (mrq->data) {
> > > > cqhci_prep_task_desc(mrq, cq_host, tag);
> > > >
> > > > @@ -619,14 +631,12 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
> > > > if (err) {
> > > > pr_err("%s: cqhci: failed to setup tx desc: %d\n",
> > > > mmc_hostname(mmc), err);
> > > > - return err;
> > > > + goto out_unlock;
> > > > }
> > > > } else {
> > > > cqhci_prep_dcmd_desc(mmc, mrq);
> > > > }
> > > >
> > > > - spin_lock_irqsave(&cq_host->lock, flags);
> > > > -
> > > > if (cq_host->recovery_halt) {
> > > > err = -EBUSY;
> > > > goto out_unlock;
> > > >
> > >
> > > Please try the following instead:
> > >
> > >
> > > diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
> > > index c2e70b757dd1..dfc8d2877115 100644
> > > --- a/drivers/mmc/core/bus.c
> > > +++ b/drivers/mmc/core/bus.c
> > > @@ -399,11 +399,6 @@ void mmc_remove_card(struct mmc_card *card)
> > > mmc_remove_card_debugfs(card);
> > > #endif
> > >
> > > - if (host->cqe_enabled) {
> > > - host->cqe_ops->cqe_disable(host);
> > > - host->cqe_enabled = false;
> > > - }
> > > -
> > > if (mmc_card_present(card)) {
> > > if (mmc_host_is_spi(card->host)) {
> > > pr_info("%s: SPI card removed\n",
> > > @@ -416,6 +411,11 @@ void mmc_remove_card(struct mmc_card *card)
> > > of_node_put(card->dev.of_node);
> > > }
> > >
> > > + if (host->cqe_enabled) {
> > > + host->cqe_ops->cqe_disable(host);
> > > + host->cqe_enabled = false;
> > > + }
> > > +
> > > put_device(&card->dev);
> > > }
> > >
> > >
> > > Actually this is my first solution, it can't resolve issues 100% and just reduce possibility.
> > >
> > > One core run The another core run
> > > mmc_remove_card mmc_mq_queue_rq
> > > { {
> > >
> > > if (mmc_card_removed(mq->card)) {
> > > req->rq_flags |= RQF_QUIET;
> > > return BLK_STS_IOERR;
> > > }
> > > //pass check here
> > > device_del(&card->dev);
> >
> > Deleting the card device removes it from the block driver
> > (i.e. mmc_blk_remove()), which cleans up the request queues,
> > so the scenario you describe here should never happen.
> >
> > Can you determine if mmc_blk_remove() is called and whether
> > it cleans up blk queues?
> >
>
> yes, mmc_blk_remove is called.
> Let me run my test case. It takes at least 24 hours.

No crash found, this method can fix this problem.
Let me send out a new patch.

>
> >
> >
> > > //free resource here
> > > host->cqe_ops->cqe_disable(host);
> > >
> > > call cqhci_request
> > > //kernel dump here to access memory that is already free.
> > >
> > > } }
> > >
> > > There is one fundamental problem that there is NOT read lock when checking mmc_card_removed, and write lock for updating md->card.
> > > The risk conditions always exist between queue request and card remove.
> > >
> > > There are no issues for non-command queue host controllers, it just causes a redundant cmd sent by host, cmd will be timeout. Just an expected IO error
> > > happened. Maybe just errors code is different.
> > >
> > > But Cmd queue is different, cmd queue disabled function free memory resources. if risk conditions happen, there are kernel dump.
> > >
> > >
> > >
> >

2021-03-04 20:28:31

by Zhi Li

[permalink] [raw]
Subject: Re: [PATCH 1/1] mmc: cqhci: fix random crash when remove mmc module

On Tue, Mar 2, 2021 at 10:25 AM Adrian Hunter <[email protected]> wrote:
>
> On 2/03/21 5:12 pm, Zhi Li wrote:
> >
> >
> > On Tue, Mar 2, 2021 at 1:03 AM Adrian Hunter <[email protected] <mailto:[email protected]>> wrote:
> >
> > On 1/03/21 7:21 pm, Frank Li wrote:
> > > [ 6684.493350] Unable to handle kernel paging request at virtual address ffff800011c5b0f0
> > > [ 6684.498531] mmc0: card 0001 removed
> > > [ 6684.501556] Mem abort info:
> > > [ 6684.509681] ESR = 0x96000047
> > > [ 6684.512786] EC = 0x25: DABT (current EL), IL = 32 bits
> > > [ 6684.518394] SET = 0, FnV = 0
> > > [ 6684.521707] EA = 0, S1PTW = 0
> > > [ 6684.524998] Data abort info:
> > > [ 6684.528236] ISV = 0, ISS = 0x00000047
> > > [ 6684.532986] CM = 0, WnR = 1
> > > [ 6684.536129] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000081b22000
> > > [ 6684.543923] [ffff800011c5b0f0] pgd=00000000bffff003, p4d=00000000bffff003, pud=00000000bfffe003, pmd=00000000900e1003, pte=0000000000000000
> > > [ 6684.557915] Internal error: Oops: 96000047 [#1] PREEMPT SMP
> > > [ 6684.564240] Modules linked in: sdhci_esdhc_imx(-) sdhci_pltfm sdhci cqhci mmc_block mmc_core fsl_jr_uio caam_jr caamkeyblob_desc caamhash_desc caamalg_desc crypto_engine rng_core authenc libdes crct10dif_ce flexcan can_dev caam error [last unloaded: mmc_core]
> > > [ 6684.587281] CPU: 0 PID: 79138 Comm: kworker/0:3H Not tainted 5.10.9-01410-g3ba33182767b-dirty #10
> > > [ 6684.596160] Hardware name: Freescale i.MX8DXL EVK (DT)
> > > [ 6684.601320] Workqueue: kblockd blk_mq_run_work_fn
> > >
> > > [ 6684.606094] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
> > > [ 6684.612286] pc : cqhci_request+0x148/0x4e8 [cqhci]
> > > ^GMessage from syslogd@ at Thu Jan 1 01:51:24 1970 ...[ 6684.617085] lr : cqhci_request+0x314/0x4e8 [cqhci]
> > > [ 6684.626734] sp : ffff80001243b9f0
> > > [ 6684.630049] x29: ffff80001243b9f0 x28: ffff00002c3dd000
> > > [ 6684.635367] x27: 0000000000000001 x26: 0000000000000001
> > > [ 6684.640690] x25: ffff00002c451000 x24: 000000000000000f
> > > [ 6684.646007] x23: ffff000017e71c80 x22: ffff00002c451000
> > > [ 6684.651326] x21: ffff00002c0f3550 x20: ffff00002c0f3550
> > > [ 6684.656651] x19: ffff000017d46880 x18: ffff00002cea1500
> > > [ 6684.661977] x17: 0000000000000000 x16: 0000000000000000
> > > [ 6684.667294] x15: 000001ee628e3ed1 x14: 0000000000000278
> > > [ 6684.672610] x13: 0000000000000001 x12: 0000000000000001
> > > [ 6684.677927] x11: 0000000000000000 x10: 0000000000000000
> > > [ 6684.683243] x9 : 000000000000002b x8 : 0000000000001000
> > > [ 6684.688560] x7 : 0000000000000010 x6 : ffff00002c0f3678
> > > [ 6684.693886] x5 : 000000000000000f x4 : ffff800011c5b000
> > > [ 6684.699211] x3 : 000000000002d988 x2 : 0000000000000008
> > > [ 6684.704537] x1 : 00000000000000f0 x0 : 0002d9880008102f
> > > [ 6684.709854] Call trace:
> > > [ 6684.712313] cqhci_request+0x148/0x4e8 [cqhci]
> > > [ 6684.716803] mmc_cqe_start_req+0x58/0x68 [mmc_core]
> > > [ 6684.721698] mmc_blk_mq_issue_rq+0x460/0x810 [mmc_block]
> > > [ 6684.727018] mmc_mq_queue_rq+0x118/0x2b0 [mmc_block]
> > >
> > > cqhci_request was called after cqhci_disable.
> > >
> > > cqhci_disable cqhci_request
> > > { {
> > > dmam_free_coherent(); (1) free
> > > if(!cq_host->enable)
> > > return
> > > (2) pass check here
> > > cq_host->enable = false;
> > >
> > > task_desc= get_desc(cq_host,tag);
> > > ^^^^ crash here
> > > (3) access memory which is already free
> > >
> > > } }
> > >
> > > Signed-off-by: Frank Li <[email protected] <mailto:[email protected]>>
> > > ---
> > > drivers/mmc/host/cqhci-core.c | 18 ++++++++++++++----
> > > 1 file changed, 14 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/mmc/host/cqhci-core.c b/drivers/mmc/host/cqhci-core.c
> > > index 93b0432bb601..36d292261e50 100644
> > > --- a/drivers/mmc/host/cqhci-core.c
> > > +++ b/drivers/mmc/host/cqhci-core.c
> > > @@ -389,6 +389,7 @@ static void cqhci_off(struct mmc_host *mmc)
> > > static void cqhci_disable(struct mmc_host *mmc)
> > > {
> > > struct cqhci_host *cq_host = mmc->cqe_private;
> > > + unsigned long flags;
> > >
> > > if (!cq_host->enabled)
> > > return;
> > > @@ -397,6 +398,11 @@ static void cqhci_disable(struct mmc_host *mmc)
> > >
> > > __cqhci_disable(cq_host);
> > >
> > > + /* need wait for cqhci_request finish before free memory */
> > > + spin_lock_irqsave(&cq_host->lock, flags);
> > > + cq_host->enabled = false;
> > > + spin_unlock_irqrestore(&cq_host->lock, flags);
> > > +
> > > dmam_free_coherent(mmc_dev(mmc), cq_host->data_size,
> > > cq_host->trans_desc_base,
> > > cq_host->trans_desc_dma_base);
> > > @@ -408,7 +414,6 @@ static void cqhci_disable(struct mmc_host *mmc)
> > > cq_host->trans_desc_base = NULL;
> > > cq_host->desc_base = NULL;
> > >
> > > - cq_host->enabled = false;
> > > }
> > >
> > > static void cqhci_prep_task_desc(struct mmc_request *mrq,
> > > @@ -612,6 +617,13 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
> > > cq_host->ops->enable(mmc);
> > > }
> > >
> > > + spin_lock_irqsave(&cq_host->lock, flags);
> > > + if (!cq_host->enabled) {
> > > + pr_err("%s: cqhci: not enabled\n", mmc_hostname(mmc));
> > > + err = -EINVAL;
> > > + goto out_unlock;
> > > + }
> > > +
> > > if (mrq->data) {
> > > cqhci_prep_task_desc(mrq, cq_host, tag);
> > >
> > > @@ -619,14 +631,12 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
> > > if (err) {
> > > pr_err("%s: cqhci: failed to setup tx desc: %d\n",
> > > mmc_hostname(mmc), err);
> > > - return err;
> > > + goto out_unlock;
> > > }
> > > } else {
> > > cqhci_prep_dcmd_desc(mmc, mrq);
> > > }
> > >
> > > - spin_lock_irqsave(&cq_host->lock, flags);
> > > -
> > > if (cq_host->recovery_halt) {
> > > err = -EBUSY;
> > > goto out_unlock;
> > >
> >
> > Please try the following instead:
> >
> >
> > diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
> > index c2e70b757dd1..dfc8d2877115 100644
> > --- a/drivers/mmc/core/bus.c
> > +++ b/drivers/mmc/core/bus.c
> > @@ -399,11 +399,6 @@ void mmc_remove_card(struct mmc_card *card)
> > mmc_remove_card_debugfs(card);
> > #endif
> >
> > - if (host->cqe_enabled) {
> > - host->cqe_ops->cqe_disable(host);
> > - host->cqe_enabled = false;
> > - }
> > -
> > if (mmc_card_present(card)) {
> > if (mmc_host_is_spi(card->host)) {
> > pr_info("%s: SPI card removed\n",
> > @@ -416,6 +411,11 @@ void mmc_remove_card(struct mmc_card *card)
> > of_node_put(card->dev.of_node);
> > }
> >
> > + if (host->cqe_enabled) {
> > + host->cqe_ops->cqe_disable(host);
> > + host->cqe_enabled = false;
> > + }
> > +
> > put_device(&card->dev);
> > }
> >
> >
> > Actually this is my first solution, it can't resolve issues 100% and just reduce possibility.
> >
> > One core run The another core run
> > mmc_remove_card mmc_mq_queue_rq
> > { {
> >
> > if (mmc_card_removed(mq->card)) {
> > req->rq_flags |= RQF_QUIET;
> > return BLK_STS_IOERR;
> > }
> > //pass check here
> > device_del(&card->dev);
>
> Deleting the card device removes it from the block driver
> (i.e. mmc_blk_remove()), which cleans up the request queues,
> so the scenario you describe here should never happen.
>
> Can you determine if mmc_blk_remove() is called and whether
> it cleans up blk queues?
>

yes, mmc_blk_remove is called.
Let me run my test case. It takes at least 24 hours.

>
>
> > //free resource here
> > host->cqe_ops->cqe_disable(host);
> >
> > call cqhci_request
> > //kernel dump here to access memory that is already free.
> >
> > } }
> >
> > There is one fundamental problem that there is NOT read lock when checking mmc_card_removed, and write lock for updating md->card.
> > The risk conditions always exist between queue request and card remove.
> >
> > There are no issues for non-command queue host controllers, it just causes a redundant cmd sent by host, cmd will be timeout. Just an expected IO error
> > happened. Maybe just errors code is different.
> >
> > But Cmd queue is different, cmd queue disabled function free memory resources. if risk conditions happen, there are kernel dump.
> >
> >
> >
>