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author | Jarkko Lavinen <jlavi@iki.fi> | 2008-12-01 22:14:08 +0100 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-12-02 04:55:25 +0100 |
commit | 09a81269c7aadaec3375a7ebd9647acbb72f5a67 (patch) | |
tree | bb823a19c56cc4a9d6110485ff05acb24f2ee578 /drivers/edac/i82875p_edac.c | |
parent | i82875p_edac: fix overflow device resource setup (diff) | |
download | linux-09a81269c7aadaec3375a7ebd9647acbb72f5a67.tar.xz linux-09a81269c7aadaec3375a7ebd9647acbb72f5a67.zip |
i82875p_edac: fix module remove
Fix module removal bugs of i82875p_edac. Also i82975x_edac code seems to
have the same module removal bugs as in i82875p_edac.
The problems were:
1. In module removal i82875p_remove_one() is never called.
Variable i82875p_registered is newer changed from 1, which
guarantees i82875p_remove_one() is not called (and even if it were
called, it would be called in wrong order).
As a result, the edac_mc workque is not stopped and keeps probing.
If kernel debugging options are not enabled, user may not notice
anything going wrong.
if debugging options are enabled and I do "rmmod i82875p_edac", I
get:
edac debug: edac_pci_workq_function() checking
BUG: unable to handle kernel paging request at f882d16f
...
call trace:
[<f8834df3>] ? edac_mc_workq_function+0x55/0x7e [edac_core]
[<c0233974>] ? run_workqueue+0xd7/0x1a5
[<c023392f>] ? run_workqueue+0x92/0x1a5
[<f8834d9e>] ? edac_mc_workq_function+0x0/0x7e [edac_core]
[<c0233af9>] ? worker_thread+0xb7/0xc3
[<c0236a7b>] ? autoremove_wake_function+0x0/0x33
[<c0233a42>] ? worker_thread+0x0/0xc3
[<c0236809>] ? kthread+0x3b/0x61
[<c02367ce>] ? kthread+0x0/0x61
[<c0204587>] ? kernel_thread_helper+0x7/0x10
Fix for this is to get rid of needles variable i82875p_registered
altogether and run i82875p_remove_one() *before*
pci_unregister_driver().
2. edac_mc_del_mc() uses mci after freeing mci
edac_mc_del_mc() calls calls edac_remove_sysfs_mci_device(). The
kobject refcount of mci drops to 0 and mci is freed. After this
mci is accessed via debug print and i82875p_remove_one() still
uses mci->pvt and tries to free mci again with edac_mc_free().
The fix for this is add kobject_get(&mci->edac_mci_kobj) after
edac_mc_alloc(). Then the mci is still available after returning
from edac_mc_del_mc() with refcount 1, and mci->pvt is still
available. When i82875p_remove_one() finally calls edac_mc_free(),
this will cause kobject_put() and mci is released properly.
Signed-off-by: Jarkko Lavinen <jlavi@iki.fi>
Cc: Doug Thompson <norsk5@yahoo.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/edac/i82875p_edac.c')
-rw-r--r-- | drivers/edac/i82875p_edac.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/drivers/edac/i82875p_edac.c b/drivers/edac/i82875p_edac.c index 7f909972fecd..ebb037b78758 100644 --- a/drivers/edac/i82875p_edac.c +++ b/drivers/edac/i82875p_edac.c @@ -182,8 +182,6 @@ static struct pci_dev *mci_pdev; /* init dev: in case that AGP code has * already registered driver */ -static int i82875p_registered = 1; - static struct edac_pci_ctl_info *i82875p_pci; static void i82875p_get_error_info(struct mem_ctl_info *mci, @@ -410,6 +408,9 @@ static int i82875p_probe1(struct pci_dev *pdev, int dev_idx) goto fail0; } + /* Keeps mci available after edac_mc_del_mc() till edac_mc_free() */ + kobject_get(&mci->edac_mci_kobj); + debugf3("%s(): init mci\n", __func__); mci->dev = &pdev->dev; mci->mtype_cap = MEM_FLAG_DDR; @@ -452,6 +453,7 @@ static int i82875p_probe1(struct pci_dev *pdev, int dev_idx) return 0; fail1: + kobject_put(&mci->edac_mci_kobj); edac_mc_free(mci); fail0: @@ -579,12 +581,11 @@ static void __exit i82875p_exit(void) { debugf3("%s()\n", __func__); + i82875p_remove_one(mci_pdev); + pci_dev_put(mci_pdev); + pci_unregister_driver(&i82875p_driver); - if (!i82875p_registered) { - i82875p_remove_one(mci_pdev); - pci_dev_put(mci_pdev); - } } module_init(i82875p_init); |