On Sun, 26 Aug 2007, Matthew Wilcox wrote: > On Sun, Aug 26, 2007 at 12:52:07AM -0700, Andrew Morton wrote: > > On Sat, 25 Aug 2007 09:47:40 -0700 (PDT) bugme-daemon@xxxxxxxxxxxxxxxxxxx wrote: > > > Problem Description: I got this error message: > > > BUG: unable to handle kernel NULL pointer dereference at virtual address > > > 00000000 > > > in dmesg output when connecting a USB device. Turning off > > > CONFIG_SCSI_SCAN_ASYNC fixed the problem. Apparently there is a bug in SCSI > > > core code. > > I don't think SCSI_SCAN_ASYNC is the problem. It's probably a > coincidence. SCSI_SCAN_ASYNC doesn't touch the call-path reported in > the backtrace. It's not a coincidence. The oops occurred because of the way the async scanning routine registers new devices. See the explanation and discussion in this thread: http://marc.info/?l=linux-scsi&m=118650567017151&w=2 > In any case, if it is SCSI_SCAN_ASYNC-related, there's an outstanding > patch to fix the locking, which is slated for inclusion in 2.6.24. > http://git.kernel.org/?p=linux/kernel/git/jejb/scsi-misc-2.6.git;a=commit;h=a93a091df8232fad60867d41fbc3be855a0b78f2 I have seen exactly this same problem, and it also shows up in Bugzilla entries #8840 and #8846. The patch mentioned above did fix it. I thought (and still do think!) that the patch should go into 2.6.23 and 2.6.22-stable. Why wait for 2.6.24 for a serious bugfix? Alan Stern - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
