Messages in this thread | | | Date | Thu, 10 Feb 2011 13:41:39 -0800 | From | Randy Dunlap <> | Subject | Re: Linux 2.6.38-rc4 (other bugs: ipmi Oops) |
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On 02/10/11 12:03, Linus Torvalds wrote: > On Thu, Feb 10, 2011 at 11:34 AM, Randy Dunlap <randy.dunlap@oracle.com> wrote: >> >> Loading ipmi_si module a second time causes an Oops: >> >> [ 68.120143] RIP: 0010:[<ffffffff813fc579>] [<ffffffff813fc579>] put_driver+0x10/0x22 > > The disassembly is > > 55 push %rbp > 48 89 e5 mov %rsp,%rbp > 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > 48 ff 05 c7 af 80 01 incq 0x180afc7(%rip) # 0x180aff2 > * 48 8b 7f 60 mov 0x60(%rdi),%rdi <-- trapping instruction > e8 38 27 ec ff callq 0xffffffffffec276c > 48 ff 05 bf af 80 01 incq 0x180afbf(%rip) # 0x180affa > c9 leaveq > c3 retq > > which is the access of "drv->p" in that function: > > kobject_put(&drv->p->kobj); > > so "drv" that was passed in was just bogus. (it's > "0xffffffffa06a8430", looks like it's the DEBUG_PAGEALLOC that has > caused the page to be free'd). > >> [ 68.340115] Call Trace: >> [ 68.340115] [<ffffffff813fc64b>] driver_register+0xc0/0x1b2 >> [ 68.340115] [<ffffffff8137f5de>] pnp_register_driver+0x28/0x31 >> [ 68.340115] [<ffffffffa06b888d>] init_ipmi_si+0x1a4/0x4cd [ipmi_si] >> [ 68.340115] [<ffffffff810020a6>] do_one_initcall+0x6c/0x1e3 >> [ 68.340115] [<ffffffff810d4998>] sys_init_module+0x12b/0x307 > > And I think that - as usual - the problem is that the damn driver > cleanup is very ugly, and has this duplicate set of code to unregister > all the random crap. Except one of the duplicates is missing one case. > I think the bug was introduced by Gjorn Helgaas in commit 9e368fa011d4 > ("ipmi: add PNP discovery (ACPI namespace via PNPACPI)") which added > the acpi pnp case, but only unregistered it on the regular module exit > path, not on the "module loaded with no pnp devices" path. > > Does this patch fix it? And Corey - this is a good example of why the > code shouldn't duplicate the "unregister stuff" in the module load > error case vs the module exit path, and there should be a shared > "cleanup()" function that is called by both. Can this be cleaned up, > please? > > PATCH IS UNTESTED!
That works.
Acked-and-tested-by: Randy Dunlap <randy.dunlap@oracle.com>
thanks, -- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code ***
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