| Message ID | 20170823150143.2746796-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
On 8/23/2017 8:01 AM, Arnd Bergmann wrote: > This is an interesting regression with gcc-8, showing a harmless > warning for correct code: > > In file included from include/linux/kernel.h:13:0, > ... > from drivers/scsi/lpfc/lpfc_debugfs.c:23: > include/linux/printk.h:301:2: error: 'eq' may be used uninitialized in this function [-Werror=maybe-uninitialized] > printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__) > ^~~~~~ > In file included from drivers/scsi/lpfc/lpfc_debugfs.c:58:0: > drivers/scsi/lpfc/lpfc_debugfs.h:451:31: note: 'eq' was declared here > > I tried to come up with a reduced test case for gcc here > a few times, but every time ended up with code that is actually > wrong with older gcc versions missing the bug and gcc-8 finding > it. As this is the only false-positive -Wmaybe-uninitialized > warnign I got with gcc-8 randconfig builds, I'd suggest we > work around it. > > Making the index variable 'unsigned' is enough to shut up > the warning, as gcc can then see that comparing eqidx to > phba->io_channel_irqs is fine here. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/scsi/lpfc/lpfc_debugfs.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > looks good. Thanks Signed-off-by: James Smart <james.smart@broadcom.com> -- james
diff --git a/drivers/scsi/lpfc/lpfc_debugfs.h b/drivers/scsi/lpfc/lpfc_debugfs.h index 7b7d314af0e0..7b7f53a37fd8 100644 --- a/drivers/scsi/lpfc/lpfc_debugfs.h +++ b/drivers/scsi/lpfc/lpfc_debugfs.h @@ -450,7 +450,7 @@ lpfc_debug_dump_cq(struct lpfc_hba *phba, int qtype, int wqidx) { struct lpfc_queue *wq, *cq, *eq; char *qtypestr; - int eqidx; + unsigned int eqidx; /* fcp/nvme wq and cq are 1:1, thus same indexes */
This is an interesting regression with gcc-8, showing a harmless warning for correct code: In file included from include/linux/kernel.h:13:0, ... from drivers/scsi/lpfc/lpfc_debugfs.c:23: include/linux/printk.h:301:2: error: 'eq' may be used uninitialized in this function [-Werror=maybe-uninitialized] printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__) ^~~~~~ In file included from drivers/scsi/lpfc/lpfc_debugfs.c:58:0: drivers/scsi/lpfc/lpfc_debugfs.h:451:31: note: 'eq' was declared here I tried to come up with a reduced test case for gcc here a few times, but every time ended up with code that is actually wrong with older gcc versions missing the bug and gcc-8 finding it. As this is the only false-positive -Wmaybe-uninitialized warnign I got with gcc-8 randconfig builds, I'd suggest we work around it. Making the index variable 'unsigned' is enough to shut up the warning, as gcc can then see that comparing eqidx to phba->io_channel_irqs is fine here. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/scsi/lpfc/lpfc_debugfs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.9.0