Messages in this thread | | | From | Greg Thelen <> | Date | Mon, 13 Jun 2011 17:34:00 -0700 | Subject | Re: [PATCH] sky2: avoid using uninitialized variable |
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On Mon, Jun 13, 2011 at 3:12 PM, Stephen Hemminger <shemminger@vyatta.com> wrote: > On Mon, 13 Jun 2011 14:21:59 -0700 > Greg Thelen <gthelen@google.com> wrote: > >> I am not sure if 0 or ~0 would be a better choice in the gm_phy_read() >> error case. I used 0. A more complete solution might be to plumb up >> error handling to the callers of gm_phy_read(). >> >> == >> From 37486219a3d93881f3b2619a4b2bb21be62db7d4 Mon Sep 17 00:00:00 2001 >> From: Greg Thelen <gthelen@google.com> >> Date: Mon, 13 Jun 2011 14:09:07 -0700 >> Subject: [PATCH] sky2: avoid using uninitialized variable >> >> Prior to this change gm_phy_read() could return an uninitialized >> variable if __gm_phy_read() failed. >> >> This change returns zero in the failure case. >> >> Signed-off-by: Greg Thelen <gthelen@google.com> > > Shouldn't the callers be changed to check rather than just returning > 0 and masking the problem.
I agree that the right long term solution is to plumb the error handling up through the callers. This would involve deleting the error-free gm_phy_read() routine and replacing all calls to it with calls to error-capable __gm_phy_read(). This would require converting several routines from returning void to returning int allowing errors to propagate upwards. Notable affected routines include: sky2_phy_power_up(), sky2_wol_init(), sky2_phy_power_down(), sky2_hw_down(), sky2_mac_init(), sky2_hw_up(), sky2_phy_intr(), sky2_led(). sky2_restart() would likely have to re-queue the work item in the case of failure. Presumably sky2_poll() would return 0 if error is seen. On a related note, it also seems that gm_phy_write() callers should be checking its return value to also handle the same class of I/O errors. Testing these changes would involve injecting error values or access to certain kinds of broken hardware.
For the short term I figured that not consuming random data was a step in right direction. But I understand if you prefer to hold out for the complete solution. Unfortunately, I do not currently have time to contribute to the complete solution. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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