FAILED: patch "[PATCH] x86/process: Don't mix user/kernel regs in 64bit" failed to apply to 4.4-stable tree
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[email protected]
maintainerThe patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
Quoted 1 line
From
9fe6299dde587788f245e9f7a5a1b296fad4e8c7Mon Sep 17 00:00:00 2001
From: Jann Horn <[email protected]>
Date: Fri, 31 Aug 2018 21:41:51 +0200
Subject: [PATCH] x86/process: Don't mix user/kernel regs in 64bit
__show_regs()
When the kernel.print-fatal-signals sysctl has been enabled, a simple userspace crash will cause the kernel to write a crash dump that contains, among other things, the kernel gsbase into dmesg.
As suggested by Andy, limit output to pt_regs, FS_BASE and KERNEL_GS_BASE in this case.
This also moves the bitness-specific logic from show_regs() into process_{32,64}.c.
Fixes 45807a1df9f5 ("vdso: print fatal signals")
Signed-off-by Jann Horn <[email protected]>
Signed-off-by Thomas Gleixner <[email protected]>
Cc "H. Peter Anvin" <[email protected]>
Cc Andy Lutomirski <[email protected]>
Cc Borislav Petkov <[email protected]>
Cc Greg Kroah-Hartman <[email protected]>
arch/x86/include/asm/kdebug.h +11 -1
@@ -22,10 +22,20 @@ enum die_val { DIE_NMIUNKNOWN, }; +enum show_regs_mode { +SHOW_REGS_SHORT , +/* +* For when userspace crashed, but we don't think it's our fault, and +* therefore don't print kernel registers. +*/ +SHOW_REGS_USER , +SHOW_REGS_ALL +}; +extern void die (const char *,struct pt_regs *,long );extern int __must_check __die (const char *,struct pt_regs *,long );extern void show_stack_regs (struct pt_regs *regs); -extern void __show_regs (struct pt_regs *regs,int all); +extern void __show_regs (struct pt_regs *regs,enum show_regs_mode );extern void show_iret_regs (struct pt_regs *regs);extern unsigned long oops_begin (void );extern void oops_end (unsigned long ,struct pt_regs *,int signr);
arch/x86/kernel/dumpstack.c +3 -8
@@ -146,7 +146,7 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,* they can be printed in the right context. */ if (!partial &&on_stack (info, regs,sizeof (*regs))) { -__show_regs (regs,0 ); +__show_regs (regs,SHOW_REGS_SHORT ); }else if (partial &&on_stack (info, (void *)regs +IRET_FRAME_OFFSET ,IRET_FRAME_SIZE )) {
@@ -344,7 +344,7 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr)oops_exit ();/* Executive summary in case the oops scrolled away */ -__show_regs (&exec_summary_regs, true); +__show_regs (&exec_summary_regs,SHOW_REGS_ALL );if (!signr)return ;
@@ -407,14 +407,9 @@ void die(const char *str, struct pt_regs *regs, long err)void show_regs (struct pt_regs *regs) { -bool all = true; -show_regs_print_info (KERN_DEFAULT ); -if (IS_ENABLED (CONFIG_X86_32 )) - all = !user_mode (regs); - -__show_regs (regs, all); +__show_regs (regs,user_mode (regs) ?SHOW_REGS_USER :SHOW_REGS_ALL );/* * When in-kernel, we also print out the stack at the time of the fault..
arch/x86/kernel/process_32.c +2 -2
@@ -59,7 +59,7 @@#include <asm/intel_rdt_sched.h> #include <asm/proto.h> -void __show_regs (struct pt_regs *regs,int all) +void __show_regs (struct pt_regs *regs,enum show_regs_mode mode) {unsigned long cr0 =0L , cr2 =0L , cr3 =0L , cr4 =0L ;unsigned long d0, d1, d2, d3, d6, d7;
@@ -85,7 +85,7 @@ void __show_regs(struct pt_regs *regs, int all)printk (KERN_DEFAULT "DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x EFLAGS: %08lx\n" , (u16 )regs->ds, (u16 )regs->es, (u16 )regs->fs, gs, ss, regs->flags); -if (!all) +if (mode !=SHOW_REGS_ALL )return ; cr0 =read_cr0 ();
arch/x86/kernel/process_64.c +10 -2
@@ -62,7 +62,7 @@__visible DEFINE_PER_CPU (unsigned long ,rsp_scratch );/* Prints also some state that isn't saved in the pt_regs */ -void __show_regs (struct pt_regs *regs,int all) +void __show_regs (struct pt_regs *regs,enum show_regs_mode mode) {unsigned long cr0 =0L , cr2 =0L , cr3 =0L , cr4 =0L , fs, gs, shadowgs;unsigned long d0, d1, d2, d3, d6, d7;
@@ -87,9 +87,17 @@ void __show_regs(struct pt_regs *regs, int all)printk (KERN_DEFAULT "R13: %016lx R14: %016lx R15: %016lx\n" , regs->r13, regs->r14, regs->r15); -if (!all) +if (mode ==SHOW_REGS_SHORT )return ; +if (mode ==SHOW_REGS_USER ) { +rdmsrl (MSR_FS_BASE , fs); +rdmsrl (MSR_KERNEL_GS_BASE , shadowgs); +printk (KERN_DEFAULT "FS: %016lx GS: %016lx\n" , + fs, shadowgs); +return ; + } + asm("movl %%ds,%0" :"=r" (ds)); asm("movl %%cs,%0" :"=r" (cs)); asm("movl %%es,%0" :"=r" (es));