From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755942AbeDTQGg (ORCPT ); Fri, 20 Apr 2018 12:06:36 -0400 Received: from ivanoab5.miniserver.com ([78.31.111.25]:47144 "EHLO www.kot-begemot.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755709AbeDTQGf (ORCPT ); Fri, 20 Apr 2018 12:06:35 -0400 Subject: Re: [uml-devel] [REVIEW][PATCH 19/22] signal/um: Use force_sig_fault in relay_signal. To: "Eric W. Biederman" , linux-arch@vger.kernel.org Cc: Richard Weinberger , Jeff Dike , linux-kernel@vger.kernel.org, linux-um@lists.infradead.org, "user-mode-linux-devel@lists.sourceforge.net" References: <87604mhrnb.fsf@xmission.com> <20180420143811.9994-19-ebiederm@xmission.com> From: Anton Ivanov Message-ID: <7074fe36-27c5-ee82-9659-da703cfc91fe@kot-begemot.co.uk> Date: Fri, 20 Apr 2018 17:06:10 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180420143811.9994-19-ebiederm@xmission.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Clacks-Overhead: GNU Terry Pratchett Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/20/18 15:38, Eric W. Biederman wrote: > Today user mode linux only works on x86 and x86_64 and this allows > simplifications of relay_signal. I believe someone recently fixed the ARM port. I have not had the time to try the fixes though. I have added the new list we are migrating to the cc list. A. > > - x86 always set si_errno to 0 in fault handlers. > - x86 does not implement si_trapno. > - Only si_codes between SI_USER and SI_KERNEL have a fault address. > > Therefore warn if si_errno is set (it should never be). > Use force_sig_info in the case where we know we have a good fault. > > For signals whose content it is not clear how to relay use plain > force_sig and let the signal sending code come up with an > appropriate generic siginfo. > > Cc: Jeff Dike > Cc: Richard Weinberger > Cc: user-mode-linux-devel@lists.sourceforge.net > Signed-off-by: "Eric W. Biederman" > --- > arch/um/kernel/trap.c | 28 +++++++++++++--------------- > 1 file changed, 13 insertions(+), 15 deletions(-) > > diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c > index d4d38520c4c6..5f0ff17cd790 100644 > --- a/arch/um/kernel/trap.c > +++ b/arch/um/kernel/trap.c > @@ -296,9 +296,6 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs) > { > - struct faultinfo *fi; > - struct siginfo clean_si; > - > if (!UPT_IS_USER(regs)) { > if (sig == SIGBUS) > printk(KERN_ERR "Bus error - the host /dev/shm or /tmp " > @@ -308,29 +305,30 @@ void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs) > > arch_examine_signal(sig, regs); > > - clear_siginfo(&clean_si); > - clean_si.si_signo = si->si_signo; > - clean_si.si_errno = si->si_errno; > - clean_si.si_code = si->si_code; > + if (unlikely(si->si_errno)) { > + printk(KERN_ERR "Attempted to relay signal %d (si_code = %d) with errno %d\n", > + sig, si->si_code, si->si_errno); > + } > switch (sig) { > case SIGILL: > case SIGFPE: > case SIGSEGV: > case SIGBUS: > case SIGTRAP: > - fi = UPT_FAULTINFO(regs); > - clean_si.si_addr = (void __user *) FAULT_ADDRESS(*fi); > - current->thread.arch.faultinfo = *fi; > -#ifdef __ARCH_SI_TRAPNO > - clean_si.si_trapno = si->si_trapno; > -#endif > - break; > + if ((si->si_code > SI_USER) && (si->si_code < SI_KERNEL)) { > + struct faultinfo *fi = UPT_FAULTINFO(regs); > + current->thread.arch.faultinfo = *fi; > + force_sig_fault(sig, si->si_code, > + (void __user *)FAULT_ADDRESS(*fi), > + current); > + break; > + } > default: > printk(KERN_ERR "Attempted to relay unknown signal %d (si_code = %d)\n", > sig, si->si_code); > } > > - force_sig_info(sig, &clean_si, current); > + force_sig(sig, current); > } > > void bus_handler(int sig, struct siginfo *si, struct uml_pt_regs *regs) From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: References: <87604mhrnb.fsf@xmission.com> <20180420143811.9994-19-ebiederm@xmission.com> From: Anton Ivanov Message-ID: <7074fe36-27c5-ee82-9659-da703cfc91fe@kot-begemot.co.uk> Date: Fri, 20 Apr 2018 17:06:10 +0100 MIME-Version: 1.0 In-Reply-To: <20180420143811.9994-19-ebiederm@xmission.com> Content-Language: en-US Subject: Re: [uml-devel] [REVIEW][PATCH 19/22] signal/um: Use force_sig_fault in relay_signal. List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net To: "Eric W. Biederman" , linux-arch@vger.kernel.org Cc: Richard Weinberger , Jeff Dike , linux-um@lists.infradead.org, linux-kernel@vger.kernel.org, "user-mode-linux-devel@lists.sourceforge.net" List-ID: On 04/20/18 15:38, Eric W. Biederman wrote: > Today user mode linux only works on x86 and x86_64 and this allows > simplifications of relay_signal. I believe someone recently fixed the ARM port. I have not had the time to try the fixes though. I have added the new list we are migrating to the cc list. A. > > - x86 always set si_errno to 0 in fault handlers. > - x86 does not implement si_trapno. > - Only si_codes between SI_USER and SI_KERNEL have a fault address. > > Therefore warn if si_errno is set (it should never be). > Use force_sig_info in the case where we know we have a good fault. > > For signals whose content it is not clear how to relay use plain > force_sig and let the signal sending code come up with an > appropriate generic siginfo. > > Cc: Jeff Dike > Cc: Richard Weinberger > Cc: user-mode-linux-devel@lists.sourceforge.net > Signed-off-by: "Eric W. Biederman" > --- > arch/um/kernel/trap.c | 28 +++++++++++++--------------- > 1 file changed, 13 insertions(+), 15 deletions(-) > > diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c > index d4d38520c4c6..5f0ff17cd790 100644 > --- a/arch/um/kernel/trap.c > +++ b/arch/um/kernel/trap.c > @@ -296,9 +296,6 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs) > { > - struct faultinfo *fi; > - struct siginfo clean_si; > - > if (!UPT_IS_USER(regs)) { > if (sig == SIGBUS) > printk(KERN_ERR "Bus error - the host /dev/shm or /tmp " > @@ -308,29 +305,30 @@ void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs) > > arch_examine_signal(sig, regs); > > - clear_siginfo(&clean_si); > - clean_si.si_signo = si->si_signo; > - clean_si.si_errno = si->si_errno; > - clean_si.si_code = si->si_code; > + if (unlikely(si->si_errno)) { > + printk(KERN_ERR "Attempted to relay signal %d (si_code = %d) with errno %d\n", > + sig, si->si_code, si->si_errno); > + } > switch (sig) { > case SIGILL: > case SIGFPE: > case SIGSEGV: > case SIGBUS: > case SIGTRAP: > - fi = UPT_FAULTINFO(regs); > - clean_si.si_addr = (void __user *) FAULT_ADDRESS(*fi); > - current->thread.arch.faultinfo = *fi; > -#ifdef __ARCH_SI_TRAPNO > - clean_si.si_trapno = si->si_trapno; > -#endif > - break; > + if ((si->si_code > SI_USER) && (si->si_code < SI_KERNEL)) { > + struct faultinfo *fi = UPT_FAULTINFO(regs); > + current->thread.arch.faultinfo = *fi; > + force_sig_fault(sig, si->si_code, > + (void __user *)FAULT_ADDRESS(*fi), > + current); > + break; > + } > default: > printk(KERN_ERR "Attempted to relay unknown signal %d (si_code = %d)\n", > sig, si->si_code); > } > > - force_sig_info(sig, &clean_si, current); > + force_sig(sig, current); > } > > void bus_handler(int sig, struct siginfo *si, struct uml_pt_regs *regs) ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel