2020-04-17 05:05:06

by Feng Tang

Subject: [PATCH RFC] ipmi: use vzalloc instead of kmalloc for user creation

We met mulitple times of failure of staring bmc-watchdog,
due to the runtime memory allocation failure of order 4.

bmc-watchdog: page allocation failure: order:4, mode:0x40cc0(GFP_KERNEL|__GFP_COMP), nodemask=(null),cpuset=/,mems_allowed=0-1
CPU: 1 PID: 2571 Comm: bmc-watchdog Not tainted 5.5.0-00045-g7d6bb61d6188c #1
Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.00.01.0015.110720180833 11/07/2018
Call Trace:
dump_stack+0x66/0x8b
warn_alloc+0xfe/0x160
__alloc_pages_slowpath+0xd3e/0xd80
__alloc_pages_nodemask+0x2f0/0x340
kmalloc_order+0x18/0x70
kmalloc_order_trace+0x1d/0xb0
ipmi_create_user+0x55/0x2c0 [ipmi_msghandler]
ipmi_open+0x72/0x110 [ipmi_devintf]
chrdev_open+0xcb/0x1e0
do_dentry_open+0x1ce/0x380
path_openat+0x305/0x14f0
do_filp_open+0x9b/0x110
do_sys_open+0x1bd/0x250
do_syscall_64+0x5b/0x1f0
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Using vzalloc/vfree for creating ipmi_user heals the
problem.

Signed-off-by: Feng Tang <[email protected]>
---
drivers/char/ipmi/ipmi_msghandler.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index c48d8f0..96f1573 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -1153,7 +1153,7 @@ static void free_user_work(struct work_struct *work)
remove_work);

cleanup_srcu_struct(&user->release_barrier);
- kfree(user);
+ vfree(user);
}

int ipmi_create_user(unsigned int if_num,
@@ -1185,7 +1185,7 @@ int ipmi_create_user(unsigned int if_num,
if (rv)
return rv;

- new_user = kmalloc(sizeof(*new_user), GFP_KERNEL);
+ new_user = vzalloc(sizeof(*new_user));
if (!new_user)
return -ENOMEM;

@@ -1232,7 +1232,7 @@ int ipmi_create_user(unsigned int if_num,

out_kfree:
srcu_read_unlock(&ipmi_interfaces_srcu, index);
- kfree(new_user);
+ vfree(new_user);
return rv;
}
EXPORT_SYMBOL(ipmi_create_user);
--
2.7.4

2020-04-18 02:04:28

by Corey Minyard

Subject: Re: [PATCH RFC] ipmi: use vzalloc instead of kmalloc for user creation

On Fri, Apr 17, 2020 at 01:01:29PM +0800, Feng Tang wrote:
> We met mulitple times of failure of staring bmc-watchdog,
> due to the runtime memory allocation failure of order 4.

I'm beginning to think that using srcu was a bad idea. It made things
cleaner and easier, but it eats tons of memory. Sigh.

Applied, at least for a fix for now.

Thanks,

-corey

>
> bmc-watchdog: page allocation failure: order:4, mode:0x40cc0(GFP_KERNEL|__GFP_COMP), nodemask=(null),cpuset=/,mems_allowed=0-1
> CPU: 1 PID: 2571 Comm: bmc-watchdog Not tainted 5.5.0-00045-g7d6bb61d6188c #1
> Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.00.01.0015.110720180833 11/07/2018
> Call Trace:
> dump_stack+0x66/0x8b
> warn_alloc+0xfe/0x160
> __alloc_pages_slowpath+0xd3e/0xd80
> __alloc_pages_nodemask+0x2f0/0x340
> kmalloc_order+0x18/0x70
> kmalloc_order_trace+0x1d/0xb0
> ipmi_create_user+0x55/0x2c0 [ipmi_msghandler]
> ipmi_open+0x72/0x110 [ipmi_devintf]
> chrdev_open+0xcb/0x1e0
> do_dentry_open+0x1ce/0x380
> path_openat+0x305/0x14f0
> do_filp_open+0x9b/0x110
> do_sys_open+0x1bd/0x250
> do_syscall_64+0x5b/0x1f0
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> Using vzalloc/vfree for creating ipmi_user heals the
> problem.
>
> Signed-off-by: Feng Tang <[email protected]>
> ---
> drivers/char/ipmi/ipmi_msghandler.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> index c48d8f0..96f1573 100644
> --- a/drivers/char/ipmi/ipmi_msghandler.c
> +++ b/drivers/char/ipmi/ipmi_msghandler.c
> @@ -1153,7 +1153,7 @@ static void free_user_work(struct work_struct *work)
> remove_work);
>
> cleanup_srcu_struct(&user->release_barrier);
> - kfree(user);
> + vfree(user);
> }
>
> int ipmi_create_user(unsigned int if_num,
> @@ -1185,7 +1185,7 @@ int ipmi_create_user(unsigned int if_num,
> if (rv)
> return rv;
>
> - new_user = kmalloc(sizeof(*new_user), GFP_KERNEL);
> + new_user = vzalloc(sizeof(*new_user));
> if (!new_user)
> return -ENOMEM;
>
> @@ -1232,7 +1232,7 @@ int ipmi_create_user(unsigned int if_num,
>
> out_kfree:
> srcu_read_unlock(&ipmi_interfaces_srcu, index);
> - kfree(new_user);
> + vfree(new_user);
> return rv;
> }
> EXPORT_SYMBOL(ipmi_create_user);
> --
> 2.7.4
>

2020-04-18 02:29:15

by Feng Tang

Subject: Re: [PATCH RFC] ipmi: use vzalloc instead of kmalloc for user creation

Hi Corey,

On Fri, Apr 17, 2020 at 09:00:06PM -0500, Corey Minyard wrote:
> On Fri, Apr 17, 2020 at 01:01:29PM +0800, Feng Tang wrote:
> > We met mulitple times of failure of staring bmc-watchdog,
> > due to the runtime memory allocation failure of order 4.
>
> I'm beginning to think that using srcu was a bad idea. It made things
> cleaner and easier, but it eats tons of memory. Sigh.

Yes, I was aslo surprised when I first knew the scru_struct is
so big. I thought we may use kmem_cache to dynamically allocate
it, though there are only a few places in kernel.

> Applied, at least for a fix for now.

Thanks! It will save us a lot of troubles :)

- Feng

> Thanks,
>
> -corey
>
> >
> > bmc-watchdog: page allocation failure: order:4, mode:0x40cc0(GFP_KERNEL|__GFP_COMP), nodemask=(null),cpuset=/,mems_allowed=0-1
> > CPU: 1 PID: 2571 Comm: bmc-watchdog Not tainted 5.5.0-00045-g7d6bb61d6188c #1
> > Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.00.01.0015.110720180833 11/07/2018
> > Call Trace:
> > dump_stack+0x66/0x8b
> > warn_alloc+0xfe/0x160
> > __alloc_pages_slowpath+0xd3e/0xd80
> > __alloc_pages_nodemask+0x2f0/0x340
> > kmalloc_order+0x18/0x70
> > kmalloc_order_trace+0x1d/0xb0
> > ipmi_create_user+0x55/0x2c0 [ipmi_msghandler]
> > ipmi_open+0x72/0x110 [ipmi_devintf]
> > chrdev_open+0xcb/0x1e0
> > do_dentry_open+0x1ce/0x380
> > path_openat+0x305/0x14f0
> > do_filp_open+0x9b/0x110
> > do_sys_open+0x1bd/0x250
> > do_syscall_64+0x5b/0x1f0
> > entry_SYSCALL_64_after_hwframe+0x44/0xa9
> >
> > Using vzalloc/vfree for creating ipmi_user heals the
> > problem.
> >
> > Signed-off-by: Feng Tang <[email protected]>
> > ---
> > drivers/char/ipmi/ipmi_msghandler.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> > index c48d8f0..96f1573 100644
> > --- a/drivers/char/ipmi/ipmi_msghandler.c
> > +++ b/drivers/char/ipmi/ipmi_msghandler.c
> > @@ -1153,7 +1153,7 @@ static void free_user_work(struct work_struct *work)
> > remove_work);
> >
> > cleanup_srcu_struct(&user->release_barrier);
> > - kfree(user);
> > + vfree(user);
> > }
> >
> > int ipmi_create_user(unsigned int if_num,
> > @@ -1185,7 +1185,7 @@ int ipmi_create_user(unsigned int if_num,
> > if (rv)
> > return rv;
> >
> > - new_user = kmalloc(sizeof(*new_user), GFP_KERNEL);
> > + new_user = vzalloc(sizeof(*new_user));
> > if (!new_user)
> > return -ENOMEM;
> >
> > @@ -1232,7 +1232,7 @@ int ipmi_create_user(unsigned int if_num,
> >
> > out_kfree:
> > srcu_read_unlock(&ipmi_interfaces_srcu, index);
> > - kfree(new_user);
> > + vfree(new_user);
> > return rv;
> > }
> > EXPORT_SYMBOL(ipmi_create_user);
> > --
> > 2.7.4
> >