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Groups > linux.kernel > #1546147
| From | Geoff Lansberry <geoff@kuvee.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v3 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel |
| Date | 2016-12-22 05:20 +0100 |
| Message-ID | <sR31f-4py-7@gated-at.bofh.it> (permalink) |
| References | <sR31f-4py-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: Jaret Cantu <jaret.cantu@timesys.com>
Repeated polling attempts cause a NULL dereference error to occur.
This is because the state of the trf7970a is currently reading but
another request has been made to send a command before it has finished.
The solution is to properly kill the waiting reading (workqueue)
before failing on the send.
Signed-off-by: Geoff Lansberry <geoff@kuvee.com>
---
drivers/nfc/trf7970a.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index e3c72c6..ba5f9b8 100644
--- a/drivers/nfc/trf7970a.c
+++ b/drivers/nfc/trf7970a.c
@@ -1496,6 +1496,10 @@ static int trf7970a_send_cmd(struct nfc_digital_dev *ddev,
(trf->state != TRF7970A_ST_IDLE_RX_BLOCKED)) {
dev_err(trf->dev, "%s - Bogus state: %d\n", __func__,
trf->state);
+ if (trf->state == TRF7970A_ST_WAIT_FOR_RX_DATA ||
+ trf->state == TRF7970A_ST_WAIT_FOR_RX_DATA_CONT)
+ trf->ignore_timeout =
+ !cancel_delayed_work(&trf->timeout_work);
ret = -EIO;
goto out_err;
}
--
2.7.4
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[PATCH v3 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel Geoff Lansberry <geoff@kuvee.com> - 2016-12-22 05:20 +0100
Re: [PATCH v3 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel Mark Greer <mgreer@animalcreek.com> - 2016-12-24 07:10 +0100
Re: [PATCH v3 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel Geoff Lansberry <geoff@kuvee.com> - 2016-12-24 17:20 +0100
Re: [PATCH v3 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel Mark Greer <mgreer@animalcreek.com> - 2016-12-24 18:30 +0100
Re: [PATCH v3 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel Geoff Lansberry <geoff@kuvee.com> - 2016-12-27 15:30 +0100
Re: [PATCH v3 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel Mark Greer <mgreer@animalcreek.com> - 2017-01-03 17:50 +0100
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