[PATCH RFC POC 18/50] xtensa: commit fds on syscall exit
From: Christian Brauner <brauner@kernel.org>
Date: 2026-09-15 11:33:52
Also in:
bpf, dri-devel, io-uring, kexec, kvm, linux-alpha, linux-arm-kernel, linux-arm-msm, linux-fsdevel, linux-gpio, linux-hyperv, linux-m68k, linux-mips, linux-mm, linux-sh, linux-um, lkml, netdev, sparclinux, virtualization
Subsystem:
ptrace support, tensilica xtensa port (xtensa), the rest · Maintainers:
Oleg Nesterov, Chris Zankel, Max Filippov, Linus Torvalds
Add TIF_FD_SLOTS and test it once the system call has stored its return value. A task that reserved descriptors uses the traced path. Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> --- arch/xtensa/include/asm/thread_info.h | 2 ++ arch/xtensa/kernel/entry.S | 5 +++++ arch/xtensa/kernel/ptrace.c | 4 ++++ 3 files changed, 11 insertions(+)
diff --git a/arch/xtensa/include/asm/thread_info.h b/arch/xtensa/include/asm/thread_info.h
index 5b74dfc35ef9..0c8eb5dc8398 100644
--- a/arch/xtensa/include/asm/thread_info.h
+++ b/arch/xtensa/include/asm/thread_info.h@@ -124,6 +124,7 @@ static __always_inline struct thread_info *current_thread_info(void) #define TIF_SYSCALL_AUDIT 9 /* syscall auditing active */ #define TIF_SECCOMP 10 /* secure computing */ #define TIF_MEMDIE 11 /* is terminating due to OOM killer */ +#define TIF_FD_SLOTS 12 /* syscall prepared descriptors */ #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE) #define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
@@ -134,6 +135,7 @@ static __always_inline struct thread_info *current_thread_info(void) #define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME) #define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT) #define _TIF_SECCOMP (1<<TIF_SECCOMP) +#define _TIF_FD_SLOTS (1<<TIF_FD_SLOTS) #define _TIF_WORK_MASK (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \ _TIF_SYSCALL_TRACEPOINT | \
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 272fff587907..4b95f48736e6 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S@@ -1976,6 +1976,11 @@ ENTRY(system_call) 1: /* regs->areg[2] = return_value */ s32i abi_rv, abi_saved0, PT_AREG2 + + /* descriptors reserved by the syscall are committed in do_syscall_trace_leave */ + GET_THREAD_INFO(a4, a1) + l32i a4, a4, TI_FLAGS + bbsi.l a4, TIF_FD_SLOTS, 1f bnez abi_saved1, 1f .Lsyscall_exit: #if defined(__XTENSA_WINDOWED_ABI__)
diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c
index 364e4fdabb00..d44d62a56b85 100644
--- a/arch/xtensa/kernel/ptrace.c
+++ b/arch/xtensa/kernel/ptrace.c@@ -13,6 +13,7 @@ */ #include <linux/audit.h> +#include <linux/file.h> #include <linux/errno.h> #include <linux/hw_breakpoint.h> #include <linux/kernel.h>
@@ -571,6 +572,9 @@ void do_syscall_trace_leave(struct pt_regs *regs) { int step; + if (test_thread_flag(TIF_FD_SLOTS)) + fd_slots_commit(regs); + audit_syscall_exit(regs); if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
--
2.53.0