From: Al Viro <viro@ZenIV.linux.org.uk>
To: James Hogan <james.hogan@imgtec.com>
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v2 23/44] metag: Traps
Date: Wed, 5 Dec 2012 17:40:35 +0000 [thread overview]
Message-ID: <20121205174035.GX4939@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1354723742-6195-24-git-send-email-james.hogan@imgtec.com>
On Wed, Dec 05, 2012 at 04:08:41PM +0000, James Hogan wrote:
> +TBIRES tail_end(TBIRES State, unsigned long orig_syscall)
> +{
> + struct pt_regs *regs = (struct pt_regs *)State.Sig.pCtx;
> + unsigned long flags;
> +
> + if (user_mode(regs)) {
> + local_irq_enable();
> + /* This is actually a crucial little line - if the process
> + * needs swapping out, then this is where it happens!
> + */
> + if (need_resched())
> + schedule();
> +
> + flags = current_thread_info()->flags;
> + if (flags & (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME)) {
> + /* Note the passing in of the original syscall number.
> + * This is used for implementing signal restart.
> + */
> + do_notify_resume(regs, orig_syscall != 0,
> + orig_syscall, flags);
Owww.... So
a) you can't get there with !user_mode(regs)
b) you handle only one signal (what happens if you fail sigframe
allocation, BTW? Sure, you get SIGSEGV delivered. And don't handle it.)
c) you read ->flags with no protection whatsoever. It should be
done *before* you enable interrupts, and rechecked after you've done
do_notify_resume() and redisabled them. The same for schedule(). It really
should be a loop; take a look at how it's done on arm and alpha - there that
loop is in C, not in asm glue.
d) looks like your sigreturn is, indeed, broken. It should *not* have
syscall restart logics triggered at all.
next prev parent reply other threads:[~2012-12-05 17:40 UTC|newest]
Thread overview: 125+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-05 16:08 [PATCH v2 00/44] Meta Linux Kernel Port James Hogan
2012-12-05 16:08 ` [PATCH v2 01/44] asm-generic/io.h: remove asm/cacheflush.h include James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 02/44] asm-generic/unistd.h: handle symbol prefixes in cond_syscall James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 03/44] Add CONFIG_HAVE_64BIT_ALIGNED_STRUCT for taskstats James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-08 3:43 ` H. Peter Anvin
2012-12-10 10:22 ` James Hogan
2012-12-10 12:55 ` Geert Uytterhoeven
2012-12-10 12:55 ` Geert Uytterhoeven
2012-12-17 9:51 ` James Hogan
2012-12-17 19:11 ` David Miller
2012-12-05 16:08 ` [PATCH v2 04/44] trace/ring_buffer: handle 64bit aligned structs James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-08 1:24 ` Steven Rostedt
2012-12-10 10:27 ` James Hogan
2012-12-10 10:27 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 05/44] Revert some of "binfmt_elf: cleanups" James Hogan
2012-12-05 16:08 ` James Hogan
[not found] ` <1354723742-6195-1-git-send-email-james.hogan-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>
2012-12-05 16:08 ` [PATCH v2 06/44] of/vendor-prefixes: add Imagination Technologies James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 22:28 ` Grant Likely
2012-12-05 22:28 ` Grant Likely
2012-12-06 9:24 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 07/44] metag: Add MAINTAINERS entry James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 08/44] metag: Headers for core arch constants James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 09/44] metag: Header for core memory mapped registers James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 10/44] metag: Boot James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 11/44] metag; TBX header James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 12/44] metag: TBX source James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 18:53 ` Joe Perches
2012-12-05 18:53 ` Joe Perches
2012-12-06 9:35 ` James Hogan
2012-12-06 12:59 ` Joe Perches
2012-12-06 15:03 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 13/44] metag: Cache/TLB handling James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 14/44] metag: Memory management James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 15/44] metag: Memory handling James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 16/44] metag: Huge TLB James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 17/44] metag: Highmem support James Hogan
2012-12-05 16:08 ` [PATCH v2 18/44] metag: TCM support James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 19/44] metag: Signal handling James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 17:16 ` Al Viro
2012-12-06 11:17 ` James Hogan
2012-12-06 22:09 ` [braindump][RFC] signals and syscall restarts (Re: [PATCH v2 19/44] metag: Signal handling) Al Viro
2012-12-08 7:44 ` Al Viro
2012-12-15 16:26 ` Jonas Bonn
2012-12-15 17:07 ` Al Viro
2012-12-08 18:14 ` Al Viro
2012-12-08 18:14 ` Al Viro
2012-12-12 9:44 ` James Hogan
2012-12-10 10:40 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 20/44] metag: Device tree James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 21/44] metag: ptrace James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 22/44] metag: Time keeping James Hogan
2013-01-04 10:05 ` Vineet Gupta
2013-01-04 12:21 ` James Hogan
2013-01-04 12:48 ` Vineet Gupta
2013-01-04 13:11 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 23/44] metag: Traps James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 17:40 ` Al Viro [this message]
2012-12-06 11:43 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 24/44] metag: IRQ handling James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 25/44] metag: System Calls James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 26/44] metag: Scheduling/Process management James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 27/44] metag: Module support James Hogan
2012-12-05 16:08 ` [PATCH v2 28/44] metag: Atomics, locks and bitops James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 29/44] metag: Basic documentation James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 30/44] metag: SMP support James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 31/44] metag: DMA James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 32/44] metag: Optimised library functions James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 33/44] metag: Stack unwinding James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 34/44] metag: Various other headers James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 35/44] mm: define VM_GROWSUP for CONFIG_METAG James Hogan
2012-12-05 16:08 ` [PATCH v2 36/44] Add metag to various Kconfig dependency lists James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 37/44] metag: Build infrastructure James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 38/44] metag: Perf James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 39/44] metag: ftrace support James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 40/44] scripts/checkstack.pl: Add metag support James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:08 ` [PATCH v2 41/44] metag: OProfile James Hogan
2012-12-05 16:08 ` James Hogan
2012-12-05 16:09 ` [PATCH v2 42/44] metag: Add JTAG Debug Adapter (DA) support James Hogan
2012-12-05 16:09 ` [PATCH v2 43/44] tty/metag_da: Add metag DA TTY driver James Hogan
2012-12-05 16:09 ` James Hogan
2012-12-05 17:24 ` Alan Cox
2013-01-04 14:11 ` James Hogan
2013-01-04 17:00 ` Alan Cox
2013-01-07 11:30 ` James Hogan
2013-01-07 11:54 ` Alan Cox
2012-12-05 16:09 ` [PATCH v2 44/44] fs: imgdafs: Add IMG DAFS filesystem for metag James Hogan
2012-12-05 17:11 ` [PATCH v2 00/44] Meta Linux Kernel Port Al Viro
2012-12-05 18:39 ` Al Viro
2012-12-18 16:09 ` James Hogan
2012-12-06 9:19 ` James Hogan
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