From: Vineet Gupta <Vineet.Gupta1@synopsys.com> To: <viro@ZenIV.linux.org.uk> Cc: <linux-arch@vger.kernel.org>, <linux-kernel@vger.kernel.org>, Vineet Gupta <Vineet.Gupta1@synopsys.com> Subject: [PATCH 2/2] ARC: [Review] Prevent incorrect syscall restarts Date: Fri, 28 Dec 2012 18:12:37 +0530 [thread overview] Message-ID: <1356698557-9000-2-git-send-email-vgupta@synopsys.com> (raw) In-Reply-To: <1356698557-9000-1-git-send-email-vgupta@synopsys.com> Per Al Viro's "signals for dummies" https://lkml.org/lkml/2012/12/6/366 there are 3 golden rules for (not) restarting syscalls: " What we need to guarantee is * restarts do not happen on signals caught in interrupts or exceptions * restarts do not happen on signals caught in sigreturn() * restart should happen only once, even if we get through do_signal() many times." ARC Port already handled #1, this patch fixes #2 and #3. We use the additional state in pt_regs->orig_r8 to ckh if restarting has already been done once. Thanks to Al Viro for spotting this. Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- arch/arc/include/asm/ptrace.h | 3 +++ arch/arc/kernel/signal.c | 12 ++++++++---- 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h index 7daa3a6..caf216e 100644 --- a/arch/arc/include/asm/ptrace.h +++ b/arch/arc/include/asm/ptrace.h @@ -93,6 +93,9 @@ struct user_regs_struct { #define in_syscall(regs) (regs->orig_r8 & orig_r8_IS_SCALL) #define in_brkpt_trap(regs) (regs->orig_r8 & orig_r8_IS_BRKPT) +#define syscall_wont_restart(regs) (regs->orig_r8 |= orig_r8_IS_SCALL_RESTARTED) +#define syscall_restartable(regs) !(regs->orig_r8 & orig_r8_IS_SCALL_RESTARTED) + #define current_pt_regs() \ ({ \ /* open-coded current_thread_info() */ \ diff --git a/arch/arc/kernel/signal.c b/arch/arc/kernel/signal.c index 464af3f..6671968 100644 --- a/arch/arc/kernel/signal.c +++ b/arch/arc/kernel/signal.c @@ -137,6 +137,9 @@ SYSCALL_DEFINE0(rt_sigreturn) if (do_sigaltstack(&sf->uc.uc_stack, NULL, regs->sp) == -EFAULT) goto badframe; + /* Don't restart from sigreturn */ + syscall_wont_restart(regs); + return regs->r0; badframe: @@ -331,13 +334,13 @@ void do_signal(struct pt_regs *regs) signr = get_signal_to_deliver(&info, &ka, regs, NULL); - /* Are we from a system call? */ - restart_scall = in_syscall(regs); + restart_scall = in_syscall(regs) && syscall_restartable(regs); if (signr > 0) { - if (restart_scall) + if (restart_scall) { arc_restart_syscall(&ka, regs); - + syscall_wont_restart(regs); /* No more restarts */ + } handle_signal(signr, &ka, &info, regs); return; } @@ -352,6 +355,7 @@ void do_signal(struct pt_regs *regs) regs->r8 = __NR_restart_syscall; regs->ret -= 4; } + syscall_wont_restart(regs); /* No more restarts */ } /* If there's no signal to deliver, restore the saved sigmask back */ -- 1.7.4.1
WARNING: multiple messages have this Message-ID (diff)
From: Vineet Gupta <Vineet.Gupta1@synopsys.com> To: viro@ZenIV.linux.org.uk Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Vineet Gupta <Vineet.Gupta1@synopsys.com> Subject: [PATCH 2/2] ARC: [Review] Prevent incorrect syscall restarts Date: Fri, 28 Dec 2012 18:12:37 +0530 [thread overview] Message-ID: <1356698557-9000-2-git-send-email-vgupta@synopsys.com> (raw) In-Reply-To: <1356698557-9000-1-git-send-email-vgupta@synopsys.com> Per Al Viro's "signals for dummies" https://lkml.org/lkml/2012/12/6/366 there are 3 golden rules for (not) restarting syscalls: " What we need to guarantee is * restarts do not happen on signals caught in interrupts or exceptions * restarts do not happen on signals caught in sigreturn() * restart should happen only once, even if we get through do_signal() many times." ARC Port already handled #1, this patch fixes #2 and #3. We use the additional state in pt_regs->orig_r8 to ckh if restarting has already been done once. Thanks to Al Viro for spotting this. Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- arch/arc/include/asm/ptrace.h | 3 +++ arch/arc/kernel/signal.c | 12 ++++++++---- 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h index 7daa3a6..caf216e 100644 --- a/arch/arc/include/asm/ptrace.h +++ b/arch/arc/include/asm/ptrace.h @@ -93,6 +93,9 @@ struct user_regs_struct { #define in_syscall(regs) (regs->orig_r8 & orig_r8_IS_SCALL) #define in_brkpt_trap(regs) (regs->orig_r8 & orig_r8_IS_BRKPT) +#define syscall_wont_restart(regs) (regs->orig_r8 |= orig_r8_IS_SCALL_RESTARTED) +#define syscall_restartable(regs) !(regs->orig_r8 & orig_r8_IS_SCALL_RESTARTED) + #define current_pt_regs() \ ({ \ /* open-coded current_thread_info() */ \ diff --git a/arch/arc/kernel/signal.c b/arch/arc/kernel/signal.c index 464af3f..6671968 100644 --- a/arch/arc/kernel/signal.c +++ b/arch/arc/kernel/signal.c @@ -137,6 +137,9 @@ SYSCALL_DEFINE0(rt_sigreturn) if (do_sigaltstack(&sf->uc.uc_stack, NULL, regs->sp) == -EFAULT) goto badframe; + /* Don't restart from sigreturn */ + syscall_wont_restart(regs); + return regs->r0; badframe: @@ -331,13 +334,13 @@ void do_signal(struct pt_regs *regs) signr = get_signal_to_deliver(&info, &ka, regs, NULL); - /* Are we from a system call? */ - restart_scall = in_syscall(regs); + restart_scall = in_syscall(regs) && syscall_restartable(regs); if (signr > 0) { - if (restart_scall) + if (restart_scall) { arc_restart_syscall(&ka, regs); - + syscall_wont_restart(regs); /* No more restarts */ + } handle_signal(signr, &ka, &info, regs); return; } @@ -352,6 +355,7 @@ void do_signal(struct pt_regs *regs) regs->r8 = __NR_restart_syscall; regs->ret -= 4; } + syscall_wont_restart(regs); /* No more restarts */ } /* If there's no signal to deliver, restore the saved sigmask back */ -- 1.7.4.1
next prev parent reply other threads:[~2012-12-28 12:43 UTC|newest] Thread overview: 141+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-11-07 9:47 [RFC Patch v1 00/31] Synopsys ARC Linux kernel Port Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 01/31] ARC: Generic Headers Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 02/31] ARC: irqflags Vineet Gupta 2012-11-12 19:50 ` Thomas Gleixner 2013-01-01 7:44 ` Vineet Gupta 2013-01-01 7:44 ` Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 03/31] ARC: atomic/bitops/cmpxchg/barriers Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 04/31] asm-generic headers: uaccess.h to conditionally define segment_eq() Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 05/31] ARC: uaccess friends Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 06/31] asm-generic headers: Allow yet more arch overrides in checksum.h Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 07/31] ARC: checksum/byteorder/swab routines Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 08/31] ARC: Fundamental ARCH data-types/defines Vineet Gupta 2012-11-08 7:10 ` Jonas Bonn 2012-11-08 18:52 ` Vineet Gupta 2012-11-08 20:36 ` Jonas Bonn 2012-11-12 13:58 ` Vineet Gupta 2012-11-12 14:12 ` Arnd Bergmann 2012-11-07 9:47 ` [RFC PATCH v1 09/31] ARC: spinlock/rwlock/mutex primitives Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 10/31] ARC: string library Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 11/31] ARC: Low level IRQ/Trap/Exception(non-MMU) Handling Vineet Gupta 2012-11-16 4:58 ` Al Viro 2012-12-27 9:00 ` Vineet Gupta 2012-12-27 9:00 ` Vineet Gupta 2012-12-27 13:29 ` Vineet Gupta 2012-12-27 13:29 ` Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 12/31] ARC: Interrupt Handling Vineet Gupta 2012-11-12 20:08 ` Thomas Gleixner 2013-01-01 10:46 ` Vineet Gupta 2013-01-01 10:46 ` Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 13/31] ARC: Non-MMU Exception Handling Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 14/31] ARC: syscall support Vineet Gupta 2012-11-07 14:21 ` Arnd Bergmann 2012-11-09 9:50 ` James Hogan 2012-11-09 9:50 ` James Hogan 2012-11-13 11:41 ` James Hogan 2012-11-13 11:41 ` James Hogan 2012-11-13 12:01 ` Jonas Bonn 2012-11-13 12:11 ` James Hogan 2012-11-13 12:11 ` James Hogan 2012-11-14 12:23 ` Arnd Bergmann 2012-11-14 12:31 ` James Hogan 2012-11-14 12:31 ` James Hogan 2012-11-13 10:13 ` Gilad Ben-Yossef 2012-11-13 10:37 ` Arnd Bergmann 2012-11-15 6:15 ` Vineet Gupta 2012-11-15 6:15 ` Vineet Gupta 2012-11-15 12:35 ` Arnd Bergmann 2013-01-17 5:13 ` Vineet Gupta 2013-01-17 5:13 ` Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 15/31] ARC: Process/scheduling/clock/Timers/Delay Management Vineet Gupta 2012-11-12 20:29 ` Thomas Gleixner 2013-01-02 7:13 ` Vineet Gupta 2013-01-02 7:13 ` Vineet Gupta 2013-01-02 8:45 ` Vineet Gupta 2013-01-02 8:45 ` Vineet Gupta 2013-01-04 13:01 ` Frederic Weisbecker 2012-11-07 9:47 ` [RFC PATCH v1 16/31] ARC: Signal handling Vineet Gupta 2012-11-16 5:26 ` Al Viro 2012-12-28 12:34 ` Vineet Gupta 2012-12-28 12:34 ` Vineet Gupta 2012-12-28 12:42 ` [PATCH 1/2] ARC: [Review] Preparing to fix incorrect syscall restarts due to signals Vineet Gupta 2012-12-28 12:42 ` Vineet Gupta 2012-12-28 12:42 ` Vineet Gupta [this message] 2012-12-28 12:42 ` [PATCH 2/2] ARC: [Review] Prevent incorrect syscall restarts Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 17/31] ARC: Cache Flush Management Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 18/31] ARC: Page Table Management Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 19/31] ARC: MMU Context Management Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 20/31] ARC: MMU Exception Handling Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 21/31] ARC: TLB flush Handling Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 22/31] ARC: Page Fault handling (incl uaccess fixup) Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 23/31] ARC: I/O and DMA Mappings Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 24/31] ARC: startup #1: low-level, setup_arch(), /proc/cpuinfo, mem init Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 25/31] ARC: [plat-arcfpga] Hooking up platform to ARC UART Vineet Gupta 2012-11-07 14:16 ` Arnd Bergmann 2013-01-07 13:10 ` Vineet Gupta 2013-01-07 13:10 ` Vineet Gupta 2013-01-07 13:46 ` Arnd Bergmann 2013-01-07 14:04 ` Vineet Gupta 2013-01-07 14:04 ` Vineet Gupta 2013-01-07 14:36 ` Arnd Bergmann 2013-01-14 7:35 ` early init dt for earlyprintk (was Re: [RFC PATCH v1 25/31] ARC: [plat-arcfpga] Hooking up platform to ARC UART) Vineet Gupta 2013-01-14 7:35 ` Vineet Gupta 2013-01-14 9:48 ` James Hogan 2013-01-14 9:48 ` James Hogan 2013-01-14 10:09 ` Vineet Gupta 2013-01-14 10:09 ` Vineet Gupta 2013-01-14 10:54 ` Arnd Bergmann 2013-01-17 7:29 ` [RFC PATCH v1 25/31] ARC: [plat-arcfpga] Hooking up platform to ARC UART Vineet Gupta 2013-01-17 7:29 ` Vineet Gupta 2013-01-17 10:52 ` Arnd Bergmann 2012-11-07 9:47 ` [RFC PATCH v1 26/31] ARC: Build system: Makefiles, Kconfig, Linker script Vineet Gupta 2012-11-07 14:13 ` Arnd Bergmann 2013-01-02 14:30 ` Vineet Gupta 2013-01-02 14:48 ` Arnd Bergmann 2013-01-03 7:58 ` Vineet Gupta 2013-01-03 7:58 ` Vineet Gupta 2013-01-03 8:25 ` Arnd Bergmann 2013-03-11 12:29 ` SYSV IPC broken for no-legacy syscall kernels (was Re: [RFC PATCH v1 26/31] ARC: Build system: Makefiles, Kconfig, Linker script) Vineet Gupta 2013-03-11 12:29 ` Vineet Gupta 2013-03-11 12:44 ` James Hogan 2013-03-11 12:44 ` James Hogan 2013-03-11 12:56 ` Vineet Gupta 2013-03-11 12:56 ` Vineet Gupta 2013-03-11 13:07 ` James Hogan 2013-03-11 13:07 ` James Hogan 2013-03-11 13:30 ` Arnd Bergmann 2013-03-11 13:48 ` Vineet Gupta 2013-03-11 13:48 ` Vineet Gupta 2013-03-11 14:50 ` Arnd Bergmann 2012-11-15 17:49 ` [RFC PATCH v1 26/31] ARC: Build system: Makefiles, Kconfig, Linker script James Hogan 2012-11-15 17:49 ` James Hogan 2012-11-15 19:30 ` Ralf Baechle 2012-11-16 6:36 ` Vineet Gupta 2012-11-16 6:36 ` Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 27/31] ARC: Last bits (stubs) to get to a running kernel with UART Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 28/31] ARC: split ret_from_fork, simplify kernel_thread() Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 29/31] ARC: switch to generic kernel_thread() Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 30/31] ARC: switch to generic kernel_execve() and sys_execve() Vineet Gupta 2012-11-16 4:08 ` Al Viro 2012-11-17 14:01 ` Vineet Gupta 2012-11-17 14:01 ` Vineet Gupta 2012-11-07 9:47 ` [RFC PATCH v1 31/31] ARC: [plat-arcfpga] defconfig Vineet Gupta 2012-11-07 14:06 ` Arnd Bergmann 2012-11-12 14:18 ` James Hogan 2012-11-12 14:18 ` James Hogan 2012-11-12 14:21 ` Arnd Bergmann 2012-11-07 14:36 ` [RFC Patch v1 00/31] Synopsys ARC Linux kernel Port Arnd Bergmann 2012-11-08 19:09 ` Vineet Gupta 2012-11-07 20:46 ` Gilad Ben-Yossef 2012-11-20 13:47 ` Pavel Machek 2012-11-20 13:49 ` Vineet Gupta 2012-11-20 13:49 ` Vineet Gupta 2012-11-20 13:59 ` Pavel Machek 2012-11-20 14:17 ` Vineet Gupta 2012-11-20 14:17 ` Vineet Gupta 2013-01-18 19:46 ` Pavel Machek 2013-01-18 22:17 ` Arnd Bergmann 2013-01-19 10:15 ` Pavel Machek 2013-01-19 12:32 ` Vineet Gupta 2013-01-19 12:32 ` Vineet Gupta 2013-01-19 17:02 ` Pavel Machek
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