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Groups > linux.kernel > #1465324
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v4 16/57] x86/entry/32: fix the end of the stack for newly forked tasks |
| Date | 2016-08-18 15:30 +0200 |
| Message-ID | <s7vyq-kW-33@gated-at.bofh.it> (permalink) |
| References | <s7vf3-dJ-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
The unwinder expects the last frame on the stack to always be at the same offset from the end of the page, which allows it to validate the stack. Calling schedule_tail() directly breaks that convention because its an asmlinkage function so its argument has to be pushed on the stack. Add a wrapper which creates a proper "end of stack" frame header before the call. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> --- arch/x86/entry/entry_32.S | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 0b56666..52b77ac 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -44,6 +44,7 @@ #include <asm/alternative-asm.h> #include <asm/asm.h> #include <asm/smap.h> +#include <asm/frame.h> .section .entry.text, "ax" @@ -204,11 +205,27 @@ POP_GS_EX .endm -ENTRY(ret_from_fork) +/* + * The unwinder expects the last frame on the stack to always be at the same + * offset from the end of the page, which allows it to validate the stack. + * Calling schedule_tail() directly would break that convention because its an + * asmlinkage function so its argument has to be pushed on the stack. This + * wrapper creates a proper "end of stack" frame header before the call. + */ +ENTRY(schedule_tail_wrapper) + FRAME_BEGIN + pushl %eax call schedule_tail popl %eax + FRAME_END + ret +ENDPROC(schedule_tail_wrapper) + +ENTRY(ret_from_fork) + call schedule_tail_wrapper + /* When we fork, we trace the syscall return in the child, too. */ movl %esp, %eax call syscall_return_slowpath @@ -216,9 +233,8 @@ ENTRY(ret_from_fork) END(ret_from_fork) ENTRY(ret_from_kernel_thread) - pushl %eax - call schedule_tail - popl %eax + call schedule_tail_wrapper + movl PT_EBP(%esp), %eax call *PT_EBX(%esp) movl $0, PT_EAX(%esp) -- 2.7.4
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[PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:20 +0200
[PATCH v4 52/57] x86/dumpstack: warn on stack recursion Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:20 +0200
[PATCH v4 46/57] x86/dumpstack: fix duplicate RIP address display in __show_regs() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:20 +0200
[PATCH v4 28/57] x86/dumpstack/ftrace: convert dump_trace() callbacks to use ftrace_graph_ret_addr() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 29/57] ftrace/x86: implement HAVE_FUNCTION_GRAPH_RET_ADDR_PTR Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 26/57] ftrace: add return address pointer to ftrace_ret_stack Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 34/57] x86/dumpstack: add get_stack_info() interface Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 23/57] proc: fix return address printk conversion specifer in /proc/<pid>/stack Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 36/57] x86/unwind: add new unwind interface and implementations Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 21/57] perf/x86: check perf_callchain_store() error Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 33/57] x86/dumpstack: simplify in_exception_stack() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 27/57] ftrace: add ftrace_graph_ret_addr() stack unwinding helpers Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 19/57] x86/entry/head/32: use local labels Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 25/57] ftrace: only allocate the ret_stack 'fp' field when needed Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 16/57] x86/entry/32: fix the end of the stack for newly forked tasks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 40/57] x86/dumpstack: convert show_trace_log_lvl() to use the new unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 39/57] oprofile/x86: convert x86_backtrace() to use the new unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 35/57] x86/dumpstack: add recursion checking for all stacks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 22/57] oprofile/x86: add regs->ip to oprofile trace Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 38/57] x86/stacktrace: convert save_stack_trace_*() to use the new unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 24/57] ftrace: remove CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST from config Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 45/57] x86/dumpstack: print any pt_regs found on the stack Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 30/57] x86/dumpstack/ftrace: mark function graph handler function as unreliable Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 47/57] x86/dumpstack: print orig_ax in __show_regs() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 44/57] x86/dumpstack: print stack identifier on its own line Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Frederic Weisbecker <fweisbec@gmail.com> - 2016-08-18 15:30 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Ingo Molnar <mingo@kernel.org> - 2016-08-18 15:40 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Steven Rostedt <rostedt@goodmis.org> - 2016-08-18 16:40 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 16:40 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Steven Rostedt <rostedt@goodmis.org> - 2016-08-18 16:50 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Ingo Molnar <mingo@kernel.org> - 2016-08-19 07:10 +0200
[PATCH v4 41/57] x86/dumpstack: remove dump_trace() and related callbacks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 31/57] x86/dumpstack/ftrace: don't print unreliable addresses in print_context_stack_bp() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 42/57] x86/entry/unwind: create stack frames for saved interrupt registers Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 20/57] x86/entry/32: rename 'error_code' to 'common_exception' Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 37/57] perf/x86: convert perf_callchain_kernel() to use the new unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 32/57] x86/dumpstack: allow preemption in show_stack_log_lvl() and dump_trace() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 12/57] x86: move _stext marker to before head code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:40 +0200
[PATCH v4 09/57] x86/dumpstack: fix x86_32 kernel_stack_pointer() previous stack access Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:40 +0200
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