Bug 885233 - strace pf lgetxattr gives bad "process_vm_readv: Bad address"
strace pf lgetxattr gives bad "process_vm_readv: Bad address"
Product: Fedora
Classification: Fedora
Component: strace (Show other bugs)
All Linux
unspecified Severity unspecified
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Assigned To: Dmitry V. Levin
Fedora Extras Quality Assurance
Depends On:
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Reported: 2012-12-07 15:53 EST by John Reiser
Modified: 2013-06-13 02:51 EDT (History)
4 users (show)

See Also:
Fixed In Version: strace-4.8-1.fc19
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2013-06-13 02:51:29 EDT
Type: Bug
Regression: ---
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RHEL 7.3 requirements from Atomic Host:
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Description John Reiser 2012-12-07 15:53:51 EST
Description of problem: The system call
   ssize_t lgetxattr (const char *path, const char *name,
                            void *value, size_t size);
specifically allows 0==value on input (the output then tells how long a subsequent call should be in order to obtain the full value), but strace always complains:
    process_vm_readv: Bad address
It's easy to get many many many spurious complaints, which slow and obscure the useful output.

The manual page says:
       An empty buffer of size zero can be passed into these calls  to  return
       the  current size of the named extended attribute, which can be used to
       estimate the size of a buffer which is sufficiently large to  hold  the
       value associated with the extended attribute.

Version-Release number of selected component (if applicable):

How reproducible: every time

Steps to Reproduce:
1. mkdir foo.dir
2. date >foo.dir/foo
3. strace cp -al foo.dir bar.dir 2>&1  |  grep readv
Actual results:
lgetxattr("foo.dir", "security.selinux"process_vm_readv: Bad address

Expected results: no complaints for lgetxattr(,,0,)

Additional info:
Comment 1 John Reiser 2012-12-07 16:02:22 EST
I guess the important info is on the following line of the strace:
   lgetxattr("foo.dir", "security.selinux"process_vm_readv: Bad address
   , 0x0, 0) = 37
where 0x0==value and 0==size.  Because 0==size, then the buffer is empty (designates a character array of length 0).  It is never allowed to access a null string (the valid length is zero), so the address does not matter, and can be 0.
Comment 2 Fedora Admin XMLRPC Client 2012-12-07 16:16:45 EST
This package has changed ownership in the Fedora Package Database.  Reassigning to the new owner of this component.
Comment 3 Dmitry V. Levin 2012-12-07 17:06:24 EST
Thanks, I've pushed a fix for this issue:
Comment 4 Dmitry V. Levin 2012-12-07 19:28:01 EST
(In reply to comment #3)
> Thanks, I've pushed a fix for this issue:

Comment 5 Fedora End Of Life 2013-04-03 15:30:28 EDT
This bug appears to have been reported against 'rawhide' during the Fedora 19 development cycle.
Changing version to '19'.

(As we did not run this process for some time, it could affect also pre-Fedora 19 development
cycle bugs. We are very sorry. It will help us with cleanup during Fedora 19 End Of Life. Thank you.)

More information and reason for this action is here:
Comment 6 Fedora Update System 2013-06-05 19:33:58 EDT
strace-4.8-1.fc19 has been submitted as an update for Fedora 19.
Comment 7 Fedora Update System 2013-06-06 13:29:48 EDT
Package strace-4.8-1.fc19:
* should fix your issue,
* was pushed to the Fedora 19 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing strace-4.8-1.fc19'
as soon as you are able to.
Please go to the following url:
then log in and leave karma (feedback).
Comment 8 Fedora Update System 2013-06-13 02:51:29 EDT
strace-4.8-1.fc19 has been pushed to the Fedora 19 stable repository.  If problems still persist, please make note of it in this bug report.

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