On 09/01/2014 08:47 PM, Russell King - ARM Linux wrote:
On Wed, Aug 27, 2014 at 02:55:46PM +0900, AKASHI Takahiro wrote:
1)
setting x0 to -ENOSYS is necessary because, otherwise, user-issued syscall(-1)
will
return a bogus value when audit tracing is on.
Please note that, on arm,
not traced traced
------ ------
syscall(-1) aborted OOPs(BUG_ON)
syscall(-3000) aborted aborted
syscall(1000) ENOSYS ENOSYS
Two points here:
1. You've found a case which causes a BUG_ON(). Where is the bug report
for this, so the problem can be investigated and resolved?
I think that I mentioned it could also happen on arm somewhere in a talk with
Will,
but don't remember exactly when.
2. What do you mean by "aborted" ?
I mean that the process will receive SIGILL and get aborted.
A system call number, like -1 and -3000, won't be trapped by *switch* statement
in asm_syscall() and end up with being signaled.
Please, if you find a problem with 32-bit ARM, report it. Don't hide it,
because hiding it can be a security issue or in the case of BUG_ON(), it
could be a denial of service issue.
As you're part of Linaro, I would have thought you'd be more responsible
in this regard - after all, Linaro is supposed to be about improving the
ARM kernel... Maybe I got that wrong, and Linaro is actually about
ensuring that the ARM kernel is stuffed full of broken features?
I thought my first priority was on arm64 (and then arm), but now that you and
Will
seem to want to see the fix first on arm, okey, I will start with arm issue.
Thanks,
-Takahiro AKASHI
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