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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-07 10:16:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-07 10:16:24 -0800
commitc6792d44d8f08451047051351dfdcc8332a028e3 (patch)
tree6a8456c6eb5b312e64131c1943bd552aed35d967 /arch
parent6fed85df5d097298d265dfcc31cf1e0c1633f41e (diff)
parent36a6c843fd0d8e02506681577e96dabd203dd8e8 (diff)
Merge tag 'core_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull syscall entry fixes from Borislav Petkov: - For syscall user dispatch, separate prctl operation from syscall redirection range specification before the API has been made official in 5.11. - Ensure tasks using the generic syscall code do trap after returning from a syscall when single-stepping is requested. * tag 'core_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: entry: Use different define for selector variable in SUD entry: Ensure trap after single-step on system call return
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/entry-common.h2
-rw-r--r--arch/x86/kernel/step.c10
2 files changed, 8 insertions, 4 deletions
diff --git a/arch/x86/include/asm/entry-common.h b/arch/x86/include/asm/entry-common.h
index 6fe54b2813c1..2b87b191b3b8 100644
--- a/arch/x86/include/asm/entry-common.h
+++ b/arch/x86/include/asm/entry-common.h
@@ -43,8 +43,6 @@ static __always_inline void arch_check_user_regs(struct pt_regs *regs)
}
#define arch_check_user_regs arch_check_user_regs
-#define ARCH_SYSCALL_EXIT_WORK (_TIF_SINGLESTEP)
-
static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,
unsigned long ti_work)
{
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
index 60d2c3798ba2..0f3c307b37b3 100644
--- a/arch/x86/kernel/step.c
+++ b/arch/x86/kernel/step.c
@@ -127,12 +127,17 @@ static int enable_single_step(struct task_struct *child)
regs->flags |= X86_EFLAGS_TF;
/*
- * Always set TIF_SINGLESTEP - this guarantees that
- * we single-step system calls etc.. This will also
+ * Always set TIF_SINGLESTEP. This will also
* cause us to set TF when returning to user mode.
*/
set_tsk_thread_flag(child, TIF_SINGLESTEP);
+ /*
+ * Ensure that a trap is triggered once stepping out of a system
+ * call prior to executing any user instruction.
+ */
+ set_task_syscall_work(child, SYSCALL_EXIT_TRAP);
+
oflags = regs->flags;
/* Set TF on the kernel stack.. */
@@ -230,6 +235,7 @@ void user_disable_single_step(struct task_struct *child)
/* Always clear TIF_SINGLESTEP... */
clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+ clear_task_syscall_work(child, SYSCALL_EXIT_TRAP);
/* But touch TF only if it was set by us.. */
if (test_and_clear_tsk_thread_flag(child, TIF_FORCED_TF))