Re: __memcpy crash with [NSData -getBytes:range:]
On Fri, Oct 10, 2008 at 2:48 AM, Daniel Kennett <[EMAIL PROTECTED]> wrote: > Hi list, > > I'm having trouble reproducing (and fixing) a rare bug that I sometimes get > reports about. > > Here's the code that causes the crash. streamPosition and length are checked > to make sure they're within the range of the NSData object: > > // Allocate a buffer. > void *buffer = malloc(length); > > // Fill the buffer with the requested bytes. > [_data getBytes:buffer range:NSMakeRange(streamPosition, length)]; > > Very occasionally, this fails with this crash: > > Exception: EXC_BAD_ACCESS (0x0001) > Codes: KERN_PROTECTION_FAILURE (0x0002) at 0x Since the address above is 0x, I suspect that buffer is NULL. Are you checking malloc's return value? You may be exceeding your process' 4GB address space. -- Clark S. Cox III [EMAIL PROTECTED] ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: __memcpy crash with [NSData -getBytes:range:]
On 10 Oct 2008, at 11:48, Daniel Kennett wrote: // Allocate a buffer. void *buffer = malloc(length); // Fill the buffer with the requested bytes. [_data getBytes:buffer range:NSMakeRange(streamPosition, length)]; Are you sure that buffer has actually been created? Maybe you are running out of RAM? Matt ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
__memcpy crash with [NSData -getBytes:range:]
Hi list, I'm having trouble reproducing (and fixing) a rare bug that I sometimes get reports about. Here's the code that causes the crash. streamPosition and length are checked to make sure they're within the range of the NSData object: // Allocate a buffer. void *buffer = malloc(length); // Fill the buffer with the requested bytes. [_data getBytes:buffer range:NSMakeRange(streamPosition, length)]; Very occasionally, this fails with this crash: Exception: EXC_BAD_ACCESS (0x0001) Codes: KERN_PROTECTION_FAILURE (0x0002) at 0x Thread 6 Crashed: 0 <<>>0x0d3f __memcpy + 1439 (cpu_capabilities.h:228) 1 com.apple.Foundation 0x9282e456 -[NSConcreteData getBytes:range:] + 267 I don't think it's the file that the NSData is created from - indeed, the customer sent me a copy of the file in question and it works perfectly on my machine. Any help in debugging this would be greatly appreciated! Surrounding the code in a @try block doesn't help - it still ends up with a hard crash (which is what I was expecting, given that is a EXC_BAD_ACCESS). Thanks, -- Daniel ___ [EMAIL PROTECTED] http://www.kennettnet.co.uk Please include previous messages in any reply you send. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
