| Message ID | 1453902342-3420391-1-git-send-email-arnd@arndb.de (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Kalle Valo |
| Headers | show |
On Wed, Jan 27, 2016 at 02:45:26PM +0100, Arnd Bergmann wrote: > To ensure we get consistent error handling here, this changes the code > to only set rlen if we actually read data correctly, which also takes > care of the warning. It may be a good idea to do the job better. Looking at the code: struct hfa384x_rid_hdr rec; spin_lock_bh(&local->baplock); res = hfa384x_setup_bap(dev, BAP0, rid, 0); if (!res) res = hfa384x_from_bap(dev, BAP0, &rec, sizeof(rec)); The only thing which initialises any of "rec" is that function call. The following lines are: if (le16_to_cpu(rec.len) == 0) { /* RID not available */ res = -ENODATA; } rlen = (le16_to_cpu(rec.len) - 1) * 2; So, why give the compiler a hard time as you're doing, why make the code harder to read. What's wrong with: spin_lock_bh(&local->baplock); res = hfa384x_setup_bap(dev, BAP0, rid, 0); if (res) goto unlock; res = hfa384x_from_bap(dev, BAP0, &rec, sizeof(rec)); if (res) goto unlock; if (le16_to_cpu(rec.len) == 0) { /* RID not available */ res = -ENODATA; goto unlock; } rlen = (le16_to_cpu(rec.len) - 1) * 2; if (exact_len && rlen != len) { printk(KERN_DEBUG "%s: hfa384x_get_rid - RID len mismatch: rid=0x%04x, len=%d (expected %d)\n", dev->name, rid, rlen, len); res = -ENODATA; goto unlock; } res = hfa384x_from_bap(dev, BAP0, buf, len); unlock: spin_unlock_bh(&local->baplock); ?
On Wednesday 27 January 2016 19:26:13 Russell King - ARM Linux wrote: > On Wed, Jan 27, 2016 at 02:45:26PM +0100, Arnd Bergmann wrote: > So, why give the compiler a hard time as you're doing, why make the code > harder to read. What's wrong with: > > spin_lock_bh(&local->baplock); > > res = hfa384x_setup_bap(dev, BAP0, rid, 0); > if (res) > goto unlock; > > res = hfa384x_from_bap(dev, BAP0, &rec, sizeof(rec)); > if (res) > goto unlock; > > if (le16_to_cpu(rec.len) == 0) { > /* RID not available */ > res = -ENODATA; > goto unlock; > } > > rlen = (le16_to_cpu(rec.len) - 1) * 2; > if (exact_len && rlen != len) { > printk(KERN_DEBUG "%s: hfa384x_get_rid - RID len mismatch: rid=0x%04x, len=%d (expected %d)\n", > dev->name, rid, rlen, len); > res = -ENODATA; > goto unlock; > } > > res = hfa384x_from_bap(dev, BAP0, buf, len); > unlock: > spin_unlock_bh(&local->baplock); > > ? > Good idea, I'll send a new version. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/wireless/intersil/hostap/hostap_hw.c b/drivers/net/wireless/intersil/hostap/hostap_hw.c index 6df3ee561d52..6dbf8ee9490a 100644 --- a/drivers/net/wireless/intersil/hostap/hostap_hw.c +++ b/drivers/net/wireless/intersil/hostap/hostap_hw.c @@ -839,12 +839,15 @@ static int hfa384x_get_rid(struct net_device *dev, u16 rid, void *buf, int len, if (!res) res = hfa384x_from_bap(dev, BAP0, &rec, sizeof(rec)); - if (le16_to_cpu(rec.len) == 0) { - /* RID not available */ - res = -ENODATA; + if (!res) { + if (le16_to_cpu(rec.len) == 0) { + /* RID not available */ + res = -ENODATA; + } + + rlen = (le16_to_cpu(rec.len) - 1) * 2; } - rlen = (le16_to_cpu(rec.len) - 1) * 2; if (!res && exact_len && rlen != len) { printk(KERN_DEBUG "%s: hfa384x_get_rid - RID len mismatch: " "rid=0x%04x, len=%d (expected %d)\n",
The driver reads a value from hfa384x_from_bap(), which may fail, and then assigns the value to a local variable. gcc detects that in in the failure case, the 'rlen' variable now contains uninitialized data: In file included from ../drivers/net/wireless/intersil/hostap/hostap_pci.c:220:0: drivers/net/wireless/intersil/hostap/hostap_hw.c: In function 'hfa384x_get_rid': drivers/net/wireless/intersil/hostap/hostap_hw.c:842:5: warning: 'rec' may be used uninitialized in this function [-Wmaybe-uninitialized] if (le16_to_cpu(rec.len) == 0) { To ensure we get consistent error handling here, this changes the code to only set rlen if we actually read data correctly, which also takes care of the warning. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/net/wireless/intersil/hostap/hostap_hw.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)