Messages in this thread Patch in this message | | | Date | Sun, 17 May 2020 10:04:20 -0000 | From | Thomas Gleixner <> | Subject | [GIT pull] objtool/urgent for v5.7-rc6 |
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Linus,
please pull the latest objtool/urgent branch from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git objtool-urgent-2020-05-17
up to: 71c95825289f: x86/unwind/orc: Fix error handling in __unwind_start()
A single bugfix for the ORC unwinder to ensure that the error flag which tells the unwinding code whether a stack trace can be trusted or not is always set correctly. This was messed up by a couple of changes in the recent past.
Thanks,
tglx
------------------> Josh Poimboeuf (1): x86/unwind/orc: Fix error handling in __unwind_start()
arch/x86/kernel/unwind_orc.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 5b0bd8581fe6..fa79e4227d3d 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -617,23 +617,23 @@ EXPORT_SYMBOL_GPL(unwind_next_frame); void __unwind_start(struct unwind_state *state, struct task_struct *task, struct pt_regs *regs, unsigned long *first_frame) { - if (!orc_init) - goto done; - memset(state, 0, sizeof(*state)); state->task = task; + if (!orc_init) + goto err; + /* * Refuse to unwind the stack of a task while it's executing on another * CPU. This check is racy, but that's ok: the unwinder has other * checks to prevent it from going off the rails. */ if (task_on_another_cpu(task)) - goto done; + goto err; if (regs) { if (user_mode(regs)) - goto done; + goto the_end; state->ip = regs->ip; state->sp = regs->sp; @@ -666,6 +666,7 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task, * generate some kind of backtrace if this happens. */ void *next_page = (void *)PAGE_ALIGN((unsigned long)state->sp); + state->error = true; if (get_stack_info(next_page, state->task, &state->stack_info, &state->stack_mask)) return; @@ -691,8 +692,9 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task, return; -done: +err: + state->error = true; +the_end: state->stack_info.type = STACK_TYPE_UNKNOWN; - return; } EXPORT_SYMBOL_GPL(__unwind_start);
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