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>
53 lines
1.7 KiB
Plaintext
53 lines
1.7 KiB
Plaintext
What: /sys/module/pch_phub/drivers/.../pch_mac
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Date: August 2010
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KernelVersion: 2.6.35
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Contact: masa-korg@dsn.okisemi.com
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Description: Write/read GbE MAC address.
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What: /sys/module/pch_phub/drivers/.../pch_firmware
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Date: August 2010
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KernelVersion: 2.6.35
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Contact: masa-korg@dsn.okisemi.com
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Description: Write/read Option ROM data.
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What: /sys/module/ehci_hcd/drivers/.../uframe_periodic_max
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Date: July 2011
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KernelVersion: 3.1
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Contact: Kirill Smelkov <kirr@mns.spb.ru>
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Description: Maximum time allowed for periodic transfers per microframe (μs)
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[ USB 2.0 sets maximum allowed time for periodic transfers per
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microframe to be 80%, that is 100 microseconds out of 125
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microseconds (full microframe).
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However there are cases, when 80% max isochronous bandwidth is
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too limiting. For example two video streams could require 110
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microseconds of isochronous bandwidth per microframe to work
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together. ]
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Through this setting it is possible to raise the limit so that
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the host controller would allow allocating more than 100
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microseconds of periodic bandwidth per microframe.
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Beware, non-standard modes are usually not thoroughly tested by
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hardware designers, and the hardware can malfunction when this
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setting differ from default 100.
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What: /sys/module/*/{coresize,initsize}
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Date: Jan 2012
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KernelVersion:»·3.3
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Contact: Kay Sievers <kay.sievers@vrfy.org>
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Description: Module size in bytes.
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What: /sys/module/*/taint
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Date: Jan 2012
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KernelVersion:»·3.3
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Contact: Kay Sievers <kay.sievers@vrfy.org>
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Description: Module taint flags:
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P - proprietary module
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O - out-of-tree module
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F - force-loaded module
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C - staging driver module
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X - unsigned module
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