From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Thu, 15 Oct 2015 13:47:56 +0100 Subject: [PATCHv3] ARM64:Fix MINSIGSTKSZ and SIGSTKSZ In-Reply-To: <20151015121241.GA26080@port70.net> References: <1444386580-10917-1-git-send-email-manjeet.p@samsung.com> <20151009103352.GK26278@arm.com> <20151015121241.GA26080@port70.net> Message-ID: <20151015124756.GB27524@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Oct 15, 2015 at 02:12:41PM +0200, Szabolcs Nagy wrote: > * Will Deacon [2015-10-09 11:33:52 +0100]: > > > On Fri, Oct 09, 2015 at 03:59:40PM +0530, Manjeet Pawar wrote: > > > MINSIGSTKSZ and SIGSTKSZ for ARM64 are not correctly set in latest kernel. > > > This patch fixes this issue. > > > > > > This issue is reported in LTP (testcase: sigaltstack02.c). > > > Testcase failed when sigaltstack() called with stack size "MINSIGSTKSZ - 1" > > > Since in Glibc-2.22, MINSIGSTKSZ is set to 5120 but in kernel > > > it is set to 2048 so testcase gets failed. > > > > > > Testcase Output: > > > sigaltstack02 1 TPASS : stgaltstack() fails, Invalid Flag value,errno:22 > > > sigaltstack02 2 TFAIL : sigaltstack() returned 0, expected -1,errno:12 > > > > I'm still unable to reproduce this failure. Is this with defconfig? > > > > > Reported Issue in Glibc Bugzilla: > > > Bugfix in Glibc-2.22: [Bug 16850] > > > https://sourceware.org/bugzilla/show_bug.cgi?id=16850 > > > > > > Signed-off-by: Akhilesh Kumar > > > Signed-off-by: Manjeet Pawar > > > Signed-off-by: Rohit Thapliyal > > > --- > > > v1 -> Changes in uapi overall header > > > v2 -> Changes done in arm64 headers > > > v3 -> Changes done in both uapi & arm64 headers > > > > > > arch/arm64/include/uapi/asm/signal.h | 3 +++ > > > include/uapi/asm-generic/signal.h | 2 ++ > > > 2 files changed, 5 insertions(+) > > > > Acked-by: Will Deacon > > > > Arnd: are you planning to take this via asm-generic, or shall I queue it > > on the arm64 fixes branch? > > > > i just noticed this and wanted to note that an old > glibc can fail on a new kernel with this patch if > an application uses MINSIGSTKSZ altstack. I was worried about that (which was also why I didn't Cc stable on this, because we shouldn't pretend that glibc and the kernel are synchronised), but the value *is* incorrect and glibc has already been updated. In other words, not merging this patch is also problematic, because we're advertising a size that's significantly too small. Would you rather we kept the old incorrect value in the kernel headers? Will