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

From: Feng Tang
Date: Fri Apr 17 2020 - 01:01:36 EST


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 <feng.tang@xxxxxxxxx>
---
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