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[Bug kprobes/1971] New: Unregister race in RCU kprobes
- From: "anil dot s dot keshavamurthy at intel dot com" <sourceware-bugzilla at sourceware dot org>
- To: systemtap at sources dot redhat dot com
- Date: 2 Dec 2005 22:56:12 -0000
- Subject: [Bug kprobes/1971] New: Unregister race in RCU kprobes
- Reply-to: sourceware-bugzilla at sourceware dot org
When registering a second kprobe at the same address as the first kprobe
(Multiple kprobes at the same address), add_aggr_kprobe() gets called. In
add_aggr_kprobe() we delete the first kprobe element from the *hash list* and
add the aggregate kprobe structure to the hash list(the first kprobe structure
is linked to aggregate kprobe)
During this process of swapping, their is a small window in which their is
*no* associated kprobe for that particular address.
If during this small window, if other cpu in kprobe_handler() code, calls
get_kprobe() for that particular address, then get_kprobe() returns null and
their by we handle our probe incorrectly leading the system to crash.
--
Summary: Unregister race in RCU kprobes
Product: systemtap
Version: unspecified
Status: NEW
Severity: normal
Priority: P2
Component: kprobes
AssignedTo: systemtap at sources dot redhat dot com
ReportedBy: anil dot s dot keshavamurthy at intel dot com
http://sourceware.org/bugzilla/show_bug.cgi?id=1971
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