On Wed, Jan 22, 2025 at 09:02:19AM +0100, Alexei Starovoitov wrote: > On Wed, Jan 22, 2025 at 5:12 AM Daniel Gomez <da.gomez@xxxxxxxxxxx> wrote: > > > > Add support for a module error injection tool. The tool > > can inject errors in the annotated module kernel functions > > such as complete_formation(), do_init_module() and > > module_enable_rodata_after_init(). Module name and module function are > > required parameters to have control over the error injection. > > > > Example: Inject error -22 to module_enable_rodata_ro_after_init for > > brd module: > > > > sudo moderr --modname=brd --modfunc=module_enable_rodata_ro_after_init \ > > --error=-22 --trace > > Monitoring module error injection... Hit Ctrl-C to end. > > MODULE ERROR FUNCTION > > brd -22 module_enable_rodata_after_init() > > > > Kernel messages: > > [ 89.463690] brd: module loaded > > [ 89.463855] brd: module_enable_rodata_ro_after_init() returned -22, > > ro_after_init data might still be writable > > > > Signed-off-by: Daniel Gomez <da.gomez@xxxxxxxxxxx> > > --- > > tools/bpf/Makefile | 13 ++- > > tools/bpf/moderr/.gitignore | 2 + > > tools/bpf/moderr/Makefile | 95 +++++++++++++++++ > > tools/bpf/moderr/moderr.bpf.c | 127 +++++++++++++++++++++++ > > tools/bpf/moderr/moderr.c | 236 ++++++++++++++++++++++++++++++++++++++++++ > > tools/bpf/moderr/moderr.h | 40 +++++++ > > 6 files changed, 510 insertions(+), 3 deletions(-) > > The tool looks useful, but we don't add tools to the kernel repo. > It has to stay out of tree. Can you clarify what do you mean? There are other tools under tools/ and tools/ bpf [1]. [1] https://lore.kernel.org/bpf/20200114184230.GA204154@krava/ I will anyway move the tool to the suggested location in the other thread. > > The value of error injection is not clear to me. > Other places in the kernel use it to test paths in the kernel > that are difficult to do otherwise. By any chance do you know which tool are they using? > These 3 functions don't seem to be in this category. Luis already answered this.
