Gabriel Krisman Bertazi 6342adcaa6 entry: Ensure trap after single-step on system call return ... Commit 2991552447 ("entry: Drop usage of TIF flags in the generic syscall code") introduced a bug on architectures using the generic syscall entry code, in which processes stopped by PTRACE_SYSCALL do not trap on syscall return after receiving a TIF_SINGLESTEP. The reason is that the meaning of TIF_SINGLESTEP flag is overloaded to cause the trap after a system call is executed, but since the above commit, the syscall call handler only checks for the SYSCALL_WORK flags on the exit work. Split the meaning of TIF_SINGLESTEP such that it only means single-step mode, and create a new type of SYSCALL_WORK to request a trap immediately after a syscall in single-step mode. In the current implementation, the SYSCALL_WORK flag shadows the TIF_SINGLESTEP flag for simplicity. Update x86 to flip this bit when a tracer enables single stepping. Fixes: 2991552447 ("entry: Drop usage of TIF flags in the generic syscall code") Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Kyle Huey <me@kylehuey.com> Link: https://lore.kernel.org/r/87h7mtc9pr.fsf_-_@collabora.com		2021-02-06 00:21:42 +01:00
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common.c	entry: Ensure trap after single-step on system call return	2021-02-06 00:21:42 +01:00
common.h	kernel: Implement selective syscall userspace redirection	2020-12-02 15:07:56 +01:00
kvm.c	Merge branch 'core/urgent' into core/entry	2020-11-04 18:14:52 +01:00
Makefile	kernel: Implement selective syscall userspace redirection	2020-12-02 15:07:56 +01:00
syscall_user_dispatch.c	kernel: Implement selective syscall userspace redirection	2020-12-02 15:07:56 +01:00