On 10 April 2018 at 01:29, <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > This is a note to let you know that I've just added the patch titled > > signal/arm: Document conflicts with SI_USER and SIGFPE > > to the 4.9-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > signal-arm-document-conflicts-with-si_user-and-sigfpe.patch > and it can be found in the queue-4.9 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. Just like v4.4.y-rc, this patch broke ARM builds for 4.9.y-rc as well https://kernelci.org/build/stable-rc/branch/linux-4.9.y/kernel/v4.9.93-278-g1614c07609f0/ Eric has already pointed out in earlier emails that this a noop so it can be dropped from all stable queues. Regards, Amit Pundir > > > From foo@baz Mon Apr 9 17:09:24 CEST 2018 > From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > Date: Thu, 17 Aug 2017 17:07:46 -0500 > Subject: signal/arm: Document conflicts with SI_USER and SIGFPE > > From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > > > [ Upstream commit 7771c66457004977b616bab785209f49d164f527 ] > > Setting si_code to 0 results in a userspace seeing an si_code of 0. > This is the same si_code as SI_USER. Posix and common sense requires > that SI_USER not be a signal specific si_code. As such this use of 0 > for the si_code is a pretty horribly broken ABI. > > Further use of si_code == 0 guaranteed that copy_siginfo_to_user saw a > value of __SI_KILL and now sees a value of SIL_KILL with the result > that uid and pid fields are copied and which might copying the si_addr > field by accident but certainly not by design. Making this a very > flakey implementation. > > Utilizing FPE_FIXME, siginfo_layout will now return SIL_FAULT and the > appropriate fields will be reliably copied. > > Possible ABI fixes includee: > - Send the signal without siginfo > - Don't generate a signal > - Possibly assign and use an appropriate si_code > - Don't handle cases which can't happen > > Cc: Russell King <rmk@xxxxxxxxxxxxxxxxxxxxxx> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Ref: 451436b7bbb2 ("[ARM] Add support code for ARM hardware vector floating point") > History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git > Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > --- > arch/arm/include/uapi/asm/siginfo.h | 13 +++++++++++++ > arch/arm/vfp/vfpmodule.c | 2 +- > 2 files changed, 14 insertions(+), 1 deletion(-) > create mode 100644 arch/arm/include/uapi/asm/siginfo.h > > --- /dev/null > +++ b/arch/arm/include/uapi/asm/siginfo.h > @@ -0,0 +1,13 @@ > +#ifndef __ASM_SIGINFO_H > +#define __ASM_SIGINFO_H > + > +#include <asm-generic/siginfo.h> > + > +/* > + * SIGFPE si_codes > + */ > +#ifdef __KERNEL__ > +#define FPE_FIXME 0 /* Broken dup of SI_USER */ > +#endif /* __KERNEL__ */ > + > +#endif > --- a/arch/arm/vfp/vfpmodule.c > +++ b/arch/arm/vfp/vfpmodule.c > @@ -257,7 +257,7 @@ static void vfp_raise_exceptions(u32 exc > > if (exceptions == VFP_EXCEPTION_ERROR) { > vfp_panic("unhandled bounce", inst); > - vfp_raise_sigfpe(0, regs); > + vfp_raise_sigfpe(FPE_FIXME, regs); > return; > } > > > > Patches currently in stable-queue which might be from ebiederm@xxxxxxxxxxxx are > > queue-4.9/signal-metag-document-a-conflict-with-si_user-with-sigfpe.patch > queue-4.9/pidns-disable-pid-allocation-if-pid_ns_prepare_proc-is-failed-in-alloc_pid.patch > queue-4.9/signal-arm-document-conflicts-with-si_user-and-sigfpe.patch > queue-4.9/signal-powerpc-document-conflicts-with-si_user-and-sigfpe-and-sigtrap.patch