Bug 460106
| Summary: | regression, rhel4.7+, on the try to read /proc/self/mem getting improper return value | ||||||
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| Product: | Red Hat Enterprise Linux 4 | Reporter: | Qian Cai <qcai> | ||||
| Component: | kernel | Assignee: | Anton Arapov <anton> | ||||
| Status: | CLOSED ERRATA | QA Contact: | Martin Jenner <mjenner> | ||||
| Severity: | urgent | Docs Contact: | |||||
| Priority: | urgent | ||||||
| Version: | 4.7 | CC: | anton, dmair, duck, nobody, prarit, tao, vgoyal | ||||
| Target Milestone: | rc | Keywords: | ZStream | ||||
| Target Release: | --- | ||||||
| Hardware: | All | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2009-05-18 19:03:31 UTC | Type: | --- | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Bug Depends On: | |||||||
| Bug Blocks: | 461304, 464747 | ||||||
| Attachments: |
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Description
Qian Cai
2008-08-26 08:31:26 UTC
I recall that Anton had a patch where he changed some proc read output ... it went into RHEL4 ~ build 68 or so. Anton, is this really a bug? P. I just went and looked at the logs for 68.10 -- Anton, your patch changed the default behavior here but I still wonder if this really is a bug. I guess Cai has a point -- "Invalid argument" indicates that the reader did something wrong... P. I do not think that my patch in 68.10 changed behaviour for this issue at all. It was addressed to completely another thing. I had something assigned in the past regarding the reading of /proc/.../mem, but somebody complaint that he was not able to read it at all by cat, and he must not, so it was closed as WONTFIX. regarding this particular report, I do not understand the issue... And just checked this on RHEL4.6, result is: "Invalid argument" NOTABUG? :-) Anton, cat /proc/self/mem on RHEL4.6 shows "Input/Output error" (-67.EL). cat /proc/self/mem on RHEL4.7 (from kernels 68.10 and onward) show "Invalid Argument". Removal of patch linux-2.6.9-Don-t-truncate-proc-PID-environ-at-4096-characters.patch changes the behavior of cat /proc/self/mem back to "Input/Output error" (As seen on dell-pe6800-01.rhts.bos.redhat.com which was installed with RHEL4.6 as a base, and binary search through kernels. I then identified the patch inux-2.6.9-Don-t-truncate-proc-PID-environ-at-4096-characters.patch as having been added in 68.10 which is where the error return value changed. After building latest-and-greatest kernel without this patch, the return code is again "Input/Output error".) The question of whether or not this is a nuisance or a real bug is still open. While it does change the return code, does it really matter? ie) Is a userspace program really going to care *why* the read failed? OTOH, "Invalid Argument" indicates that the user/reader did something wrong... P. Agreed ... I've tested it on -78 kernel. Didn't notice that. In this particular case user-space stuff shouldn't care about the return code, the program shouldn't be able to read mem this way. OTOH, I/O error is correct return code and shouldn't be changed after my patch, but it was changed... I will look into it. [...cut...] @@ -1587,7 +1634,6 @@ static struct dentry *proc_pident_lookup(struct inode *dir, case PROC_TID_MEM: case PROC_TGID_MEM: inode->i_op = &proc_mem_inode_operations; - inode->i_fop = &proc_mem_operations; break; case PROC_TID_MOUNTS: case PROC_TGID_MOUNTS: this is the problem... /me looking how this happend... Yep, it was my bad, I posted the wrongly generated patch, and nobody noticed that.... Created attachment 315182 [details]
proposed patch
I want to nominate this bug for RHEL4.7 z-stream as well, but do not have rights to put the rhel-4.7.z flag into '?' state. Anton, if this doesn't hurt customers, should it be a z-stream candidate? P. This is regression. And I can't vouch for tools customers may have... This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux maintenance release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Update release for currently deployed products. This request is not yet committed for inclusion in an Update release. Updating PM score. This bugzilla has Keywords: Regression. Since no regressions are allowed between releases, it is also being proposed as a blocker for this release. Please resolve ASAP. Committed in 78.8.EL . RPMS are available at http://people.redhat.com/vgoyal/rhel4/ *** Bug 459765 has been marked as a duplicate of this bug. *** An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2009-1024.html |