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| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2014-03-13 12:11:30 +1030 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2014-03-13 12:11:51 +1030 |
| commit | 66cc69e34e86a231fbe68d8918c6119e3b7549a3 (patch) | |
| tree | c1ea795511e9ed8ab83fda895f0151000b166629 /Documentation/ABI | |
| parent | cff26a51da5d206d3baf871e75778da44710219d (diff) | |
| download | linux-66cc69e34e86a231fbe68d8918c6119e3b7549a3.tar.bz2 | |
Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE
Users have reported being unable to trace non-signed modules loaded
within a kernel supporting module signature.
This is caused by tracepoint.c:tracepoint_module_coming() refusing to
take into account tracepoints sitting within force-loaded modules
(TAINT_FORCED_MODULE). The reason for this check, in the first place, is
that a force-loaded module may have a struct module incompatible with
the layout expected by the kernel, and can thus cause a kernel crash
upon forced load of that module on a kernel with CONFIG_TRACEPOINTS=y.
Tracepoints, however, specifically accept TAINT_OOT_MODULE and
TAINT_CRAP, since those modules do not lead to the "very likely system
crash" issue cited above for force-loaded modules.
With kernels having CONFIG_MODULE_SIG=y (signed modules), a non-signed
module is tainted re-using the TAINT_FORCED_MODULE taint flag.
Unfortunately, this means that Tracepoints treat that module as a
force-loaded module, and thus silently refuse to consider any tracepoint
within this module.
Since an unsigned module does not fit within the "very likely system
crash" category of tainting, add a new TAINT_UNSIGNED_MODULE taint flag
to specifically address this taint behavior, and accept those modules
within Tracepoints. We use the letter 'X' as a taint flag character for
a module being loaded that doesn't know how to sign its name (proposed
by Steven Rostedt).
Also add the missing 'O' entry to trace event show_module_flags() list
for the sake of completeness.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
NAKed-by: Ingo Molnar <mingo@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: David Howells <dhowells@redhat.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-module | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-module b/Documentation/ABI/testing/sysfs-module index 47064c2b1f79..b9a29cdbaccb 100644 --- a/Documentation/ABI/testing/sysfs-module +++ b/Documentation/ABI/testing/sysfs-module @@ -49,3 +49,4 @@ Description: Module taint flags: O - out-of-tree module F - force-loaded module C - staging driver module + X - unsigned module |