Messages in this thread Patch in this message | | | Subject | Re: [PATCH v2] ipmi: Fix kernel panic at ipmi_ssif_thread() | From | Corey Minyard <> | Date | Mon, 27 Mar 2017 07:32:02 -0500 |
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On 03/27/2017 02:31 AM, Joeseph Chang wrote: > From: Joeseph Chang <joechang@codeaurora.org> > > Since patch v1 touch ssif_info->multi_pos and ssif_info->multi_data > after ssif_i2c_send(). msg_written_handler can be called at any time > after ssif_i2c_send(). There is possible to have concurrent access to > ssif_info->multi_pos or ssif_info->multi_data at msg_written_handler. > > Revert patch v1 and add new local pointer "i2c_data" which point to > i2c data and size that will be sent out to avoid concurrent access in > msg_written_handler(). > > Signed-off-by: Joeseph Chang <joechang@codeaurora.org> > --- > drivers/char/ipmi/ipmi_ssif.c | 24 ++++++++++++------------ > 1 file changed, 12 insertions(+), 12 deletions(-) > > diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c > index 39346ee..f36f018 100644 > --- a/drivers/char/ipmi/ipmi_ssif.c > +++ b/drivers/char/ipmi/ipmi_ssif.c > @@ -852,6 +852,7 @@ static void msg_written_handler(struct ssif_info *ssif_info, int result, > unsigned char *data, unsigned int len) > { > int rv; > + unsigned char *i2c_data;
The variable should be in the block where it is used. The basic rule is to limit scope as much as possible.
The name is also a little vague, though not terrible.
> > /* We are single-threaded here, so no need for a lock. */ > if (result < 0) { > @@ -899,13 +900,22 @@ static void msg_written_handler(struct ssif_info *ssif_info, int result, > left = 32; > /* Length byte. */ > ssif_info->multi_data[ssif_info->multi_pos] = left; > + i2c_data = ssif_info->multi_data + ssif_info->multi_pos; > + ssif_info->multi_pos += left; > + if (left < 32) > + /* > + * Write is finished. Note that we must end > + * with a write of less than 32 bytes to > + * complete the transaction, even if it is > + * zero bytes. > + */ > + ssif_info->multi_data = NULL;
Can you make this change not relative to the previous change? Just do a "git rebase -i ...." and squash the changes.
I saw your previous emails, but I can't take those because of the comments at the top and the text from the reply. You can add comments to a submission that don't go into git, just put them after the '---" in the header.
Thanks,
-corey
> > rv = ssif_i2c_send(ssif_info, msg_written_handler, > I2C_SMBUS_WRITE, > SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE, > - ssif_info->multi_data + ssif_info->multi_pos, > + i2c_data, > I2C_SMBUS_BLOCK_DATA); > - > if (rv < 0) { > /* request failed, just return the error. */ > ssif_inc_stat(ssif_info, send_errors); > @@ -914,16 +924,6 @@ static void msg_written_handler(struct ssif_info *ssif_info, int result, > pr_info("Error from i2c_non_blocking_op(3)\n"); > msg_done_handler(ssif_info, -EIO, NULL, 0); > } > - > - ssif_info->multi_pos += left; > - if (left < 32) > - /* > - * Write is finished. Note that we must end > - * with a write of less than 32 bytes to > - * complete the transaction, even if it is > - * zero bytes. > - */ > - ssif_info->multi_data = NULL; > } else { > /* Ready to request the result. */ > unsigned long oflags, *flags;
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