diff mbox

sym53c8xx: Avoid undefined behaviour in drivers/scsi/sym53c8xx_2/sym_hipd.c:762

Message ID 20170810190849.GA12659@p100.box (mailing list archive)
State Awaiting Upstream
Delegated to: Helge Deller
Headers show

Commit Message

Helge Deller Aug. 10, 2017, 7:08 p.m. UTC
On parisc I see this UBSAN warning with a sym53c896:

 UBSAN: Undefined behaviour in ./drivers/scsi/sym53c8xx_2/sym_hipd.c:762:24
 index -1903078336 is out of range for type 'u32 [7]'

Avoid this warning by switching to dev64_ul().

Signed-off-by: Helge Deller <deller@gmx.de>

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Comments

Johannes Thumshirn Aug. 11, 2017, 7:24 a.m. UTC | #1
On Thu, Aug 10, 2017 at 09:08:49PM +0200, Helge Deller wrote:
> On parisc I see this UBSAN warning with a sym53c896:
> 
>  UBSAN: Undefined behaviour in ./drivers/scsi/sym53c8xx_2/sym_hipd.c:762:24
>  index -1903078336 is out of range for type 'u32 [7]'
> 
> Avoid this warning by switching to dev64_ul().
                            div64_ul() ^

Otherwise,
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Martin K. Petersen Aug. 15, 2017, 3:07 a.m. UTC | #2
Helge,

> On parisc I see this UBSAN warning with a sym53c896:
>
>  UBSAN: Undefined behaviour in ./drivers/scsi/sym53c8xx_2/sym_hipd.c:762:24
>  index -1903078336 is out of range for type 'u32 [7]'
>
> Avoid this warning by switching to dev64_ul().

Applied to 4.14/scsi-queue. Thank you, Helge!
diff mbox

Patch

diff --git a/drivers/scsi/sym53c8xx_2/sym_hipd.c b/drivers/scsi/sym53c8xx_2/sym_hipd.c
index 6b349e3..15ff285a9 100644
--- a/drivers/scsi/sym53c8xx_2/sym_hipd.c
+++ b/drivers/scsi/sym53c8xx_2/sym_hipd.c
@@ -759,7 +759,7 @@  static int sym_prepare_setting(struct Scsi_Host *shost, struct sym_hcb *np, stru
 	/*
 	 * Maximum synchronous period factor supported by the chip.
 	 */
-	period = (11 * div_10M[np->clock_divn - 1]) / (4 * np->clock_khz);
+	period = div64_ul(11 * div_10M[np->clock_divn - 1], 4 * np->clock_khz);
 	np->maxsync = period > 2540 ? 254 : period / 10;
 
 	/*