Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag
From: Al Viro <viro@zeniv.linux.org.uk>
Date: 2020-09-18 13:58:39
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io-uring, keyrings, linux-arch, linux-arm-kernel, linux-block, linux-fsdevel, linux-mips, linux-mm, linux-s390, linux-scsi, linux-security-module, lkml, netdev, sparclinux
On Fri, Sep 18, 2020 at 03:44:06PM +0200, Christoph Hellwig wrote:
On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote:quoted
quoted
/* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */ - return pt_regs_trap_type(current_pt_regs()) == 0x110; + return pt_regs_trap_type(current_pt_regs()) == 0x110 || + (current->flags & PF_FORCE_COMPAT);Can't say I like that approach ;-/ Reasoning about the behaviour is much harder when it's controlled like that - witness set_fs() shite...I don't particularly like it either. But do you have a better idea how to deal with io_uring vs compat tasks?
<wry> git rm fs/io_uring.c would make a good starting point </wry> Yes, I know it's not going to happen, but one can dream... Said that, why not provide a variant that would take an explicit "is it compat" argument and use it there? And have the normal one pass in_compat_syscall() to that...