Now that copy_fpregs_to_sigframe() returns boolean the individual return
codes in the related helper functions do not make sense anymore. Change
them to return boolean success/fail.
Signed-off-by: Thomas Gleixner <[email protected]>
---
arch/x86/kernel/fpu/signal.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -65,7 +65,7 @@ static inline int check_xstate_in_sigfra
/*
* Signal frame handlers.
*/
-static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
+static inline bool save_fsave_header(struct task_struct *tsk, void __user *buf)
{
if (use_fxsr()) {
struct xregs_state *xsave = &tsk->thread.fpu.state.xsave;
@@ -82,18 +82,19 @@ static inline int save_fsave_header(stru
if (__copy_to_user(buf, &env, sizeof(env)) ||
__put_user(xsave->i387.swd, &fp->status) ||
__put_user(X86_FXSR_MAGIC, &fp->magic))
- return -1;
+ return false;
} else {
struct fregs_state __user *fp = buf;
u32 swd;
+
if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
- return -1;
+ return false;
}
- return 0;
+ return true;
}
-static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
+static inline bool save_xstate_epilog(void __user *buf, int ia32_frame)
{
struct xregs_state __user *x = buf;
struct _fpx_sw_bytes *sw_bytes;
@@ -131,7 +132,7 @@ static inline int save_xstate_epilog(voi
err |= __put_user(xfeatures, (__u32 __user *)&x->header.xfeatures);
- return err;
+ return !err;
}
static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
@@ -219,10 +220,10 @@ bool copy_fpstate_to_sigframe(void __use
}
/* Save the fsave header for the 32-bit frames. */
- if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
+ if ((ia32_fxstate || !use_fxsr()) && !save_fsave_header(tsk, buf))
return false;
- if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
+ if (use_fxsr() && !save_xstate_epilog(buf_fx, ia32_fxstate))
return false;
return true;
The following commit has been merged into the x86/fpu branch of tip:
Commit-ID: 2af07f3a6e9fb81331421ca24b26a96180d792dd
Gitweb: https://git.kernel.org/tip/2af07f3a6e9fb81331421ca24b26a96180d792dd
Author: Thomas Gleixner <[email protected]>
AuthorDate: Wed, 08 Sep 2021 15:29:34 +02:00
Committer: Borislav Petkov <[email protected]>
CommitterDate: Tue, 14 Sep 2021 21:10:03 +02:00
x86/fpu/signal: Change return type of copy_fpregs_to_sigframe() helpers to boolean
Now that copy_fpregs_to_sigframe() returns boolean the individual return
codes in the related helper functions do not make sense anymore. Change
them to return boolean success/fail.
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/kernel/fpu/signal.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 7ce396d..1d10fe9 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -65,7 +65,7 @@ setfx:
/*
* Signal frame handlers.
*/
-static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
+static inline bool save_fsave_header(struct task_struct *tsk, void __user *buf)
{
if (use_fxsr()) {
struct xregs_state *xsave = &tsk->thread.fpu.state.xsave;
@@ -82,18 +82,19 @@ static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
if (__copy_to_user(buf, &env, sizeof(env)) ||
__put_user(xsave->i387.swd, &fp->status) ||
__put_user(X86_FXSR_MAGIC, &fp->magic))
- return -1;
+ return false;
} else {
struct fregs_state __user *fp = buf;
u32 swd;
+
if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
- return -1;
+ return false;
}
- return 0;
+ return true;
}
-static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
+static inline bool save_xstate_epilog(void __user *buf, int ia32_frame)
{
struct xregs_state __user *x = buf;
struct _fpx_sw_bytes *sw_bytes;
@@ -131,7 +132,7 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
err |= __put_user(xfeatures, (__u32 __user *)&x->header.xfeatures);
- return err;
+ return !err;
}
static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
@@ -218,10 +219,10 @@ retry:
}
/* Save the fsave header for the 32-bit frames. */
- if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
+ if ((ia32_fxstate || !use_fxsr()) && !save_fsave_header(tsk, buf))
return false;
- if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
+ if (use_fxsr() && !save_xstate_epilog(buf_fx, ia32_fxstate))
return false;
return true;
On Wed, 8 Sept 2021 at 15:30, Thomas Gleixner <[email protected]> wrote:
>
> Now that copy_fpregs_to_sigframe() returns boolean the individual return
> codes in the related helper functions do not make sense anymore. Change
> them to return boolean success/fail.
>
> Signed-off-by: Thomas Gleixner <[email protected]>
When I build and boot (qemu_x86_64) a defconfig kernel on from todays
next tag next-20210921 I see the following segmentation fault
2021-09-21T10:11:45 <6>[ 1.622922] mount (89) used greatest stack
depth: 14384 bytes left
2021-09-21T10:11:45 <6>[ 1.664760] EXT4-fs (sda): re-mounted. Opts:
(null). Quota mode: none.
2021-09-21T10:11:45 <6>[ 1.691041] mkdir (92) used greatest stack
depth: 14312 bytes left
2021-09-21T10:11:45 <6>[ 1.713201] mount (93) used greatest stack
depth: 13720 bytes left
2021-09-21T10:11:46 Starting syslogd: /etc/init.d/rcS: line 12: 101
Segmentation fault $i start
I did a bisection and found this as the faulty patch [1]. When I
revert this patch I can't see the issue.
We noticed that function 'save_xstate_epilog()' changes the polarity
of its return code for one of the return statements, and for its only
caller. but not for the other return statement.
I tried this patch and I couldn't see the segmentation fault.
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 445c57c9c539..61eeebc04427 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -104,7 +104,7 @@ static inline int save_xstate_epilog(void __user
*buf, int ia32_frame)
err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
if (!use_xsave())
- return err;
+ return !err;
err |= __put_user(FP_XSTATE_MAGIC2,
(__u32 __user *)(buf + fpu_user_xstate_size));
Cheers,
Anders
[1] http://ix.io/3zxf
> ---
> arch/x86/kernel/fpu/signal.c | 17 +++++++++--------
> 1 file changed, 9 insertions(+), 8 deletions(-)
>
> --- a/arch/x86/kernel/fpu/signal.c
> +++ b/arch/x86/kernel/fpu/signal.c
> @@ -65,7 +65,7 @@ static inline int check_xstate_in_sigfra
> /*
> * Signal frame handlers.
> */
> -static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
> +static inline bool save_fsave_header(struct task_struct *tsk, void __user *buf)
> {
> if (use_fxsr()) {
> struct xregs_state *xsave = &tsk->thread.fpu.state.xsave;
> @@ -82,18 +82,19 @@ static inline int save_fsave_header(stru
> if (__copy_to_user(buf, &env, sizeof(env)) ||
> __put_user(xsave->i387.swd, &fp->status) ||
> __put_user(X86_FXSR_MAGIC, &fp->magic))
> - return -1;
> + return false;
> } else {
> struct fregs_state __user *fp = buf;
> u32 swd;
> +
> if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
> - return -1;
> + return false;
> }
>
> - return 0;
> + return true;
> }
>
> -static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
> +static inline bool save_xstate_epilog(void __user *buf, int ia32_frame)
> {
> struct xregs_state __user *x = buf;
> struct _fpx_sw_bytes *sw_bytes;
> @@ -131,7 +132,7 @@ static inline int save_xstate_epilog(voi
>
> err |= __put_user(xfeatures, (__u32 __user *)&x->header.xfeatures);
>
> - return err;
> + return !err;
> }
>
> static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
> @@ -219,10 +220,10 @@ bool copy_fpstate_to_sigframe(void __use
> }
>
> /* Save the fsave header for the 32-bit frames. */
> - if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
> + if ((ia32_fxstate || !use_fxsr()) && !save_fsave_header(tsk, buf))
> return false;
>
> - if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
> + if (use_fxsr() && !save_xstate_epilog(buf_fx, ia32_fxstate))
> return false;
>
> return true;
>
On Tue, Sep 21, 2021 at 12:58:34PM +0200, Anders Roxell wrote:
> On Wed, 8 Sept 2021 at 15:30, Thomas Gleixner <[email protected]> wrote:
> >
> > Now that copy_fpregs_to_sigframe() returns boolean the individual return
> > codes in the related helper functions do not make sense anymore. Change
> > them to return boolean success/fail.
> >
> > Signed-off-by: Thomas Gleixner <[email protected]>
>
> When I build and boot (qemu_x86_64) a defconfig kernel on from todays
> next tag next-20210921 I see the following segmentation fault
>
> 2021-09-21T10:11:45 <6>[ 1.622922] mount (89) used greatest stack
> depth: 14384 bytes left
> 2021-09-21T10:11:45 <6>[ 1.664760] EXT4-fs (sda): re-mounted. Opts:
> (null). Quota mode: none.
> 2021-09-21T10:11:45 <6>[ 1.691041] mkdir (92) used greatest stack
> depth: 14312 bytes left
> 2021-09-21T10:11:45 <6>[ 1.713201] mount (93) used greatest stack
> depth: 13720 bytes left
> 2021-09-21T10:11:46 Starting syslogd: /etc/init.d/rcS: line 12: 101
> Segmentation fault $i start
>
>
> I did a bisection and found this as the faulty patch [1]. When I
> revert this patch I can't see the issue.
>
> We noticed that function 'save_xstate_epilog()' changes the polarity
> of its return code for one of the return statements, and for its only
> caller. but not for the other return statement.
>
> I tried this patch and I couldn't see the segmentation fault.
>
> diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
> index 445c57c9c539..61eeebc04427 100644
> --- a/arch/x86/kernel/fpu/signal.c
> +++ b/arch/x86/kernel/fpu/signal.c
> @@ -104,7 +104,7 @@ static inline int save_xstate_epilog(void __user
> *buf, int ia32_frame)
> err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
>
> if (!use_xsave())
> - return err;
> + return !err;
>
> err |= __put_user(FP_XSTATE_MAGIC2,
> (__u32 __user *)(buf + fpu_user_xstate_size));
Thank for the report. Our CI watching tip has also been super red over
the past day or so; all boot failures.
Andrew Cooper reported this diff to me on IRC; I tested out the above
and it fixes the boot failure for us.
Tested-by: Nick Desaulniers <[email protected]>
Link: https://github.com/ClangBuiltLinux/linux/issues/1461
Our CI used -cpu Nehalem for qemu since KVM isn't exposed to the bots on
github actions, FWIW.
https://github.com/ClangBuiltLinux/boot-utils/blob/2edbca214f9a4cabd3f138ea029015d6cf52d110/boot-qemu.sh#L278-L288
>
>
>
> Cheers,
> Anders
> [1] http://ix.io/3zxf
>
> > ---
> > arch/x86/kernel/fpu/signal.c | 17 +++++++++--------
> > 1 file changed, 9 insertions(+), 8 deletions(-)
> >
> > --- a/arch/x86/kernel/fpu/signal.c
> > +++ b/arch/x86/kernel/fpu/signal.c
> > @@ -65,7 +65,7 @@ static inline int check_xstate_in_sigfra
> > /*
> > * Signal frame handlers.
> > */
> > -static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
> > +static inline bool save_fsave_header(struct task_struct *tsk, void __user *buf)
> > {
> > if (use_fxsr()) {
> > struct xregs_state *xsave = &tsk->thread.fpu.state.xsave;
> > @@ -82,18 +82,19 @@ static inline int save_fsave_header(stru
> > if (__copy_to_user(buf, &env, sizeof(env)) ||
> > __put_user(xsave->i387.swd, &fp->status) ||
> > __put_user(X86_FXSR_MAGIC, &fp->magic))
> > - return -1;
> > + return false;
> > } else {
> > struct fregs_state __user *fp = buf;
> > u32 swd;
> > +
> > if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
> > - return -1;
> > + return false;
> > }
> >
> > - return 0;
> > + return true;
> > }
> >
> > -static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
> > +static inline bool save_xstate_epilog(void __user *buf, int ia32_frame)
> > {
> > struct xregs_state __user *x = buf;
> > struct _fpx_sw_bytes *sw_bytes;
> > @@ -131,7 +132,7 @@ static inline int save_xstate_epilog(voi
> >
> > err |= __put_user(xfeatures, (__u32 __user *)&x->header.xfeatures);
> >
> > - return err;
> > + return !err;
> > }
> >
> > static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
> > @@ -219,10 +220,10 @@ bool copy_fpstate_to_sigframe(void __use
> > }
> >
> > /* Save the fsave header for the 32-bit frames. */
> > - if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
> > + if ((ia32_fxstate || !use_fxsr()) && !save_fsave_header(tsk, buf))
> > return false;
> >
> > - if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
> > + if (use_fxsr() && !save_xstate_epilog(buf_fx, ia32_fxstate))
> > return false;
> >
> > return true;
> >
On Tue, Sep 21 2021 at 12:58, Anders Roxell wrote:
> On Wed, 8 Sept 2021 at 15:30, Thomas Gleixner <[email protected]> wrote:
>>
>> Now that copy_fpregs_to_sigframe() returns boolean the individual return
>> codes in the related helper functions do not make sense anymore. Change
>> them to return boolean success/fail.
>>
>> Signed-off-by: Thomas Gleixner <[email protected]>
>
> When I build and boot (qemu_x86_64) a defconfig kernel on from todays
> next tag next-20210921 I see the following segmentation fault
>
> 2021-09-21T10:11:45 <6>[ 1.622922] mount (89) used greatest stack
> depth: 14384 bytes left
> 2021-09-21T10:11:45 <6>[ 1.664760] EXT4-fs (sda): re-mounted. Opts:
> (null). Quota mode: none.
> 2021-09-21T10:11:45 <6>[ 1.691041] mkdir (92) used greatest stack
> depth: 14312 bytes left
> 2021-09-21T10:11:45 <6>[ 1.713201] mount (93) used greatest stack
> depth: 13720 bytes left
> 2021-09-21T10:11:46 Starting syslogd: /etc/init.d/rcS: line 12: 101
> Segmentation fault $i start
>
>
> I did a bisection and found this as the faulty patch [1]. When I
> revert this patch I can't see the issue.
>
> We noticed that function 'save_xstate_epilog()' changes the polarity
> of its return code for one of the return statements, and for its only
> caller. but not for the other return statement.
>
> I tried this patch and I couldn't see the segmentation fault.
>
> diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
> index 445c57c9c539..61eeebc04427 100644
> --- a/arch/x86/kernel/fpu/signal.c
> +++ b/arch/x86/kernel/fpu/signal.c
> @@ -104,7 +104,7 @@ static inline int save_xstate_epilog(void __user
> *buf, int ia32_frame)
> err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
>
> if (!use_xsave())
> - return err;
> + return !err;
Oops. Good catch. Care to send a proper patch for this?
Thanks,
tglx
+ Andrew (sorry, I messed up your address on the previous message)
On Tue, Sep 21, 2021 at 10:36 AM Nick Desaulniers
<[email protected]> wrote:
>
> On Tue, Sep 21, 2021 at 12:58:34PM +0200, Anders Roxell wrote:
> > On Wed, 8 Sept 2021 at 15:30, Thomas Gleixner <[email protected]> wrote:
> > >
> > > Now that copy_fpregs_to_sigframe() returns boolean the individual return
> > > codes in the related helper functions do not make sense anymore. Change
> > > them to return boolean success/fail.
> > >
> > > Signed-off-by: Thomas Gleixner <[email protected]>
> >
> > When I build and boot (qemu_x86_64) a defconfig kernel on from todays
> > next tag next-20210921 I see the following segmentation fault
> >
> > 2021-09-21T10:11:45 <6>[ 1.622922] mount (89) used greatest stack
> > depth: 14384 bytes left
> > 2021-09-21T10:11:45 <6>[ 1.664760] EXT4-fs (sda): re-mounted. Opts:
> > (null). Quota mode: none.
> > 2021-09-21T10:11:45 <6>[ 1.691041] mkdir (92) used greatest stack
> > depth: 14312 bytes left
> > 2021-09-21T10:11:45 <6>[ 1.713201] mount (93) used greatest stack
> > depth: 13720 bytes left
> > 2021-09-21T10:11:46 Starting syslogd: /etc/init.d/rcS: line 12: 101
> > Segmentation fault $i start
> >
> >
> > I did a bisection and found this as the faulty patch [1]. When I
> > revert this patch I can't see the issue.
> >
> > We noticed that function 'save_xstate_epilog()' changes the polarity
> > of its return code for one of the return statements, and for its only
> > caller. but not for the other return statement.
> >
> > I tried this patch and I couldn't see the segmentation fault.
> >
> > diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
> > index 445c57c9c539..61eeebc04427 100644
> > --- a/arch/x86/kernel/fpu/signal.c
> > +++ b/arch/x86/kernel/fpu/signal.c
> > @@ -104,7 +104,7 @@ static inline int save_xstate_epilog(void __user
> > *buf, int ia32_frame)
> > err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
> >
> > if (!use_xsave())
> > - return err;
> > + return !err;
> >
> > err |= __put_user(FP_XSTATE_MAGIC2,
> > (__u32 __user *)(buf + fpu_user_xstate_size));
>
> Thank for the report. Our CI watching tip has also been super red over
> the past day or so; all boot failures.
>
> Andrew Cooper reported this diff to me on IRC; I tested out the above
> and it fixes the boot failure for us.
>
> Tested-by: Nick Desaulniers <[email protected]>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1461
>
> Our CI used -cpu Nehalem for qemu since KVM isn't exposed to the bots on
> github actions, FWIW.
> https://github.com/ClangBuiltLinux/boot-utils/blob/2edbca214f9a4cabd3f138ea029015d6cf52d110/boot-qemu.sh#L278-L288
>
> >
> >
> >
> > Cheers,
> > Anders
> > [1] http://ix.io/3zxf
> >
> > > ---
> > > arch/x86/kernel/fpu/signal.c | 17 +++++++++--------
> > > 1 file changed, 9 insertions(+), 8 deletions(-)
> > >
> > > --- a/arch/x86/kernel/fpu/signal.c
> > > +++ b/arch/x86/kernel/fpu/signal.c
> > > @@ -65,7 +65,7 @@ static inline int check_xstate_in_sigfra
> > > /*
> > > * Signal frame handlers.
> > > */
> > > -static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
> > > +static inline bool save_fsave_header(struct task_struct *tsk, void __user *buf)
> > > {
> > > if (use_fxsr()) {
> > > struct xregs_state *xsave = &tsk->thread.fpu.state.xsave;
> > > @@ -82,18 +82,19 @@ static inline int save_fsave_header(stru
> > > if (__copy_to_user(buf, &env, sizeof(env)) ||
> > > __put_user(xsave->i387.swd, &fp->status) ||
> > > __put_user(X86_FXSR_MAGIC, &fp->magic))
> > > - return -1;
> > > + return false;
> > > } else {
> > > struct fregs_state __user *fp = buf;
> > > u32 swd;
> > > +
> > > if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
> > > - return -1;
> > > + return false;
> > > }
> > >
> > > - return 0;
> > > + return true;
> > > }
> > >
> > > -static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
> > > +static inline bool save_xstate_epilog(void __user *buf, int ia32_frame)
> > > {
> > > struct xregs_state __user *x = buf;
> > > struct _fpx_sw_bytes *sw_bytes;
> > > @@ -131,7 +132,7 @@ static inline int save_xstate_epilog(voi
> > >
> > > err |= __put_user(xfeatures, (__u32 __user *)&x->header.xfeatures);
> > >
> > > - return err;
> > > + return !err;
> > > }
> > >
> > > static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
> > > @@ -219,10 +220,10 @@ bool copy_fpstate_to_sigframe(void __use
> > > }
> > >
> > > /* Save the fsave header for the 32-bit frames. */
> > > - if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
> > > + if ((ia32_fxstate || !use_fxsr()) && !save_fsave_header(tsk, buf))
> > > return false;
> > >
> > > - if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
> > > + if (use_fxsr() && !save_xstate_epilog(buf_fx, ia32_fxstate))
> > > return false;
> > >
> > > return true;
> > >
--
Thanks,
~Nick Desaulniers
On Tue, 21 Sept 2021 at 22:13, Thomas Gleixner <[email protected]> wrote:
>
> On Tue, Sep 21 2021 at 12:58, Anders Roxell wrote:
> > On Wed, 8 Sept 2021 at 15:30, Thomas Gleixner <[email protected]> wrote:
> >>
> >> Now that copy_fpregs_to_sigframe() returns boolean the individual return
> >> codes in the related helper functions do not make sense anymore. Change
> >> them to return boolean success/fail.
> >>
> >> Signed-off-by: Thomas Gleixner <[email protected]>
> >
> > When I build and boot (qemu_x86_64) a defconfig kernel on from todays
> > next tag next-20210921 I see the following segmentation fault
> >
> > 2021-09-21T10:11:45 <6>[ 1.622922] mount (89) used greatest stack
> > depth: 14384 bytes left
> > 2021-09-21T10:11:45 <6>[ 1.664760] EXT4-fs (sda): re-mounted. Opts:
> > (null). Quota mode: none.
> > 2021-09-21T10:11:45 <6>[ 1.691041] mkdir (92) used greatest stack
> > depth: 14312 bytes left
> > 2021-09-21T10:11:45 <6>[ 1.713201] mount (93) used greatest stack
> > depth: 13720 bytes left
> > 2021-09-21T10:11:46 Starting syslogd: /etc/init.d/rcS: line 12: 101
> > Segmentation fault $i start
> >
> >
> > I did a bisection and found this as the faulty patch [1]. When I
> > revert this patch I can't see the issue.
> >
> > We noticed that function 'save_xstate_epilog()' changes the polarity
> > of its return code for one of the return statements, and for its only
> > caller. but not for the other return statement.
> >
> > I tried this patch and I couldn't see the segmentation fault.
> >
> > diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
> > index 445c57c9c539..61eeebc04427 100644
> > --- a/arch/x86/kernel/fpu/signal.c
> > +++ b/arch/x86/kernel/fpu/signal.c
> > @@ -104,7 +104,7 @@ static inline int save_xstate_epilog(void __user
> > *buf, int ia32_frame)
> > err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
> >
> > if (!use_xsave())
> > - return err;
> > + return !err;
>
> Oops. Good catch. Care to send a proper patch for this?
Yes I can try to do that.
Cheers,
Anders