Kernel/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2025-01-04 04:06:26 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

x86/ftrace: Rebalance RSB

Browse Source 
ftrace_regs_caller() uses a PUSH;RET pattern to tail-call into a
direct-call function, this unbalances the RSB, fix that.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.823216933@infradead.org
This commit is contained in:
Peter Zijlstra 2022-09-15 13:11:36 +02:00
parent eac828eaef
commit 36b64f1012
1 changed files with 11 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
arch/x86/kernel/ftrace_64.S
View File

@ -271,6 +271,17 @@ SYM_INNER_LABEL(ftrace_regs_caller_end, SYM_L_GLOBAL)
/* Restore flags */
popfq
UNWIND_HINT_FUNC
/*
* The above left an extra return value on the stack; effectively
* doing a tail-call without using a register. This PUSH;RET
* pattern unbalances the RSB, inject a pointless CALL to rebalance.
*/
ANNOTATE_INTRA_FUNCTION_CALL
CALL .Ldo_rebalance
int3
.Ldo_rebalance:
add $8, %rsp
RET
SYM_FUNC_END(ftrace_regs_caller)