| Message ID | 20181102154426.1951776-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | scsi: myrs: avoid stack overflow warning | expand |
On 11/2/18 4:44 PM, Arnd Bergmann wrote: > Putting a 1024 byte data structure on the stack is generally a bad idea. > On 32-bit systems, it also triggers a compile-time warning when building > with -Og: > > drivers/scsi/myrs.c: In function 'myrs_get_ctlr_info': > drivers/scsi/myrs.c:212:1: error: the frame size of 1028 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] > > We only really need three members of the structure, so just read them > manually here instead of copying the entire structure. > > Fixes: 77266186397c ("scsi: myrs: Add Mylex RAID controller (SCSI interface)") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/scsi/myrs.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > diff --git a/drivers/scsi/myrs.c b/drivers/scsi/myrs.c > index 0264a2e2bc19..b8d54ef8cf6d 100644 > --- a/drivers/scsi/myrs.c > +++ b/drivers/scsi/myrs.c > @@ -163,9 +163,12 @@ static unsigned char myrs_get_ctlr_info(struct myrs_hba *cs) > dma_addr_t ctlr_info_addr; > union myrs_sgl *sgl; > unsigned char status; > - struct myrs_ctlr_info old; > + unsigned short ldev_present, ldev_critical, ldev_offline; > + > + ldev_present = cs->ctlr_info->ldev_present; > + ldev_critical = cs->ctlr_info->ldev_critical; > + ldev_offline = cs->ctlr_info->ldev_offline; > > - memcpy(&old, cs->ctlr_info, sizeof(struct myrs_ctlr_info)); > ctlr_info_addr = dma_map_single(&cs->pdev->dev, cs->ctlr_info, > sizeof(struct myrs_ctlr_info), > DMA_FROM_DEVICE); > @@ -198,9 +201,9 @@ static unsigned char myrs_get_ctlr_info(struct myrs_hba *cs) > cs->ctlr_info->rbld_active + > cs->ctlr_info->exp_active != 0) > cs->needs_update = true; > - if (cs->ctlr_info->ldev_present != old.ldev_present || > - cs->ctlr_info->ldev_critical != old.ldev_critical || > - cs->ctlr_info->ldev_offline != old.ldev_offline) > + if (cs->ctlr_info->ldev_present != ldev_present || > + cs->ctlr_info->ldev_critical != ldev_critical || > + cs->ctlr_info->ldev_offline != ldev_offline) > shost_printk(KERN_INFO, cs->host, > "Logical drive count changes (%d/%d/%d)\n", > cs->ctlr_info->ldev_critical, > Reviewed-by: Hannes Reinecke <hare@suse.com> Cheers, Hannes
Arnd, > Putting a 1024 byte data structure on the stack is generally a bad idea. > On 32-bit systems, it also triggers a compile-time warning when building > with -Og: Applied to 4.20/scsi-fixes, thanks! -- Martin K. Petersen Oracle Linux Engineering
diff --git a/drivers/scsi/myrs.c b/drivers/scsi/myrs.c index 0264a2e2bc19..b8d54ef8cf6d 100644 --- a/drivers/scsi/myrs.c +++ b/drivers/scsi/myrs.c @@ -163,9 +163,12 @@ static unsigned char myrs_get_ctlr_info(struct myrs_hba *cs) dma_addr_t ctlr_info_addr; union myrs_sgl *sgl; unsigned char status; - struct myrs_ctlr_info old; + unsigned short ldev_present, ldev_critical, ldev_offline; + + ldev_present = cs->ctlr_info->ldev_present; + ldev_critical = cs->ctlr_info->ldev_critical; + ldev_offline = cs->ctlr_info->ldev_offline; - memcpy(&old, cs->ctlr_info, sizeof(struct myrs_ctlr_info)); ctlr_info_addr = dma_map_single(&cs->pdev->dev, cs->ctlr_info, sizeof(struct myrs_ctlr_info), DMA_FROM_DEVICE); @@ -198,9 +201,9 @@ static unsigned char myrs_get_ctlr_info(struct myrs_hba *cs) cs->ctlr_info->rbld_active + cs->ctlr_info->exp_active != 0) cs->needs_update = true; - if (cs->ctlr_info->ldev_present != old.ldev_present || - cs->ctlr_info->ldev_critical != old.ldev_critical || - cs->ctlr_info->ldev_offline != old.ldev_offline) + if (cs->ctlr_info->ldev_present != ldev_present || + cs->ctlr_info->ldev_critical != ldev_critical || + cs->ctlr_info->ldev_offline != ldev_offline) shost_printk(KERN_INFO, cs->host, "Logical drive count changes (%d/%d/%d)\n", cs->ctlr_info->ldev_critical,
Putting a 1024 byte data structure on the stack is generally a bad idea. On 32-bit systems, it also triggers a compile-time warning when building with -Og: drivers/scsi/myrs.c: In function 'myrs_get_ctlr_info': drivers/scsi/myrs.c:212:1: error: the frame size of 1028 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] We only really need three members of the structure, so just read them manually here instead of copying the entire structure. Fixes: 77266186397c ("scsi: myrs: Add Mylex RAID controller (SCSI interface)") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/scsi/myrs.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) -- 2.18.0