Linux kernel development work - see feature branches https://git.zx2c4.com/linux-dev/atom/arch/csky/lib/error-inject.c?h=linus%2Fmaster 2020-07-31T01:52:07Z 2020-07-31T01:52:07Z Guo Ren guoren@linux.alibaba.com 2020-07-28T16:30:46Z urn:sha1:71e193d7cbcfc988c3802e15261bd807171adb6b Inspired by the commit 42d038c4fb00 ("arm64: Add support for function error injection"), this patch supports function error injection for csky. This patch mainly support two functions: one is regs_set_return_value() which is used to overwrite the return value; the another function is override_function_with_return() which is to override the probed function returning and jump to its caller. Test log: cd /sys/kernel/debug/fail_function/ echo sys_clone > inject echo 100 > probability echo 1 > interval ls / [ 108.644163] FAULT_INJECTION: forcing a failure. [ 108.644163] name fail_function, interval 1, probability 100, space 0, times 1 [ 108.647799] CPU: 0 PID: 104 Comm: sh Not tainted 5.8.0-rc5+ #46 [ 108.648384] Call Trace: [ 108.649339] [<8005eed4>] walk_stackframe+0x0/0xf0 [ 108.649679] [<8005f16a>] show_stack+0x32/0x5c [ 108.649927] [<8040f9d2>] dump_stack+0x6e/0x9c [ 108.650271] [<80406f7e>] should_fail+0x15e/0x1ac [ 108.650720] [<80118ba8>] fei_kprobe_handler+0x28/0x5c [ 108.651519] [<80754110>] kprobe_breakpoint_handler+0x144/0x1cc [ 108.652289] [<8005d6da>] trap_c+0x8e/0x110 [ 108.652816] [<8005ce8c>] csky_trap+0x5c/0x70 -sh: can't fork: Invalid argument Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Cc: Arnd Bergmann <arnd@arndb.de>