From: "Jarkko Sakkinen" <jarkko@kernel.org>
To: "Haitao Huang" <haitao.huang@linux.intel.com>,
<dave.hansen@linux.intel.com>, <tj@kernel.org>,
<linux-kernel@vger.kernel.org>, <linux-sgx@vger.kernel.org>,
<cgroups@vger.kernel.org>, "Zefan Li" <lizefan.x@bytedance.com>,
"Johannes Weiner" <hannes@cmpxchg.org>
Cc: <vipinsh@google.com>, <kai.huang@intel.com>,
<reinette.chatre@intel.com>, <zhiquan1.li@intel.com>,
<kristen@linux.intel.com>
Subject: Re: [PATCH] cgroup/misc: Fix an overflow
Date: Mon, 17 Jul 2023 18:55:32 +0000 [thread overview]
Message-ID: <CU4OCLEHU1S5.359W394902648@seitikki> (raw)
In-Reply-To: <20230717184719.85523-1-haitao.huang@linux.intel.com>
On Mon Jul 17, 2023 at 6:47 PM UTC, Haitao Huang wrote:
> The variable 'new_usage' in misc_cg_try_charge() may overflow if it
> becomes above INT_MAX. This was observed when I implement the new SGX
> EPC cgroup[1] as a misc cgroup and test on a platform with large SGX EPC
> sizes.
>
> Change type of new_usage to long from int and check overflow.
>
> Fixes: a72232eabdfcf ("cgroup: Add misc cgroup controller")
> Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
>
> [1] https://lore.kernel.org/linux-sgx/20230712230202.47929-1-haitao.huang@linux.intel.com/
> ---
> kernel/cgroup/misc.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
> index fe3e8a0eb7ed..ff9f900981a3 100644
> --- a/kernel/cgroup/misc.c
> +++ b/kernel/cgroup/misc.c
> @@ -143,7 +143,7 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
> struct misc_cg *i, *j;
> int ret;
> struct misc_res *res;
> - int new_usage;
> + long new_usage;
>
> if (!(valid_type(type) && cg && READ_ONCE(misc_res_capacity[type])))
> return -EINVAL;
> @@ -153,10 +153,10 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
>
> for (i = cg; i; i = parent_misc(i)) {
> res = &i->res[type];
> -
This is extra noise in the patch, please remove the change.
> new_usage = atomic_long_add_return(amount, &res->usage);
> if (new_usage > READ_ONCE(res->max) ||
> - new_usage > READ_ONCE(misc_res_capacity[type])) {
> + new_usage > READ_ONCE(misc_res_capacity[type]) ||
> + new_usage < 0) {
> ret = -EBUSY;
> goto err_charge;
> }
> --
> 2.25.1
BR, Jarkko
next prev parent reply other threads:[~2023-07-17 18:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-17 18:47 [PATCH] cgroup/misc: Fix an overflow Haitao Huang
2023-07-17 18:51 ` Tejun Heo
2023-07-17 18:55 ` Jarkko Sakkinen [this message]
2023-07-17 18:57 ` Tejun Heo
2023-07-17 19:01 ` Haitao Huang
2023-07-17 20:19 ` Haitao Huang
2023-07-17 20:37 ` Tejun Heo
2023-07-18 1:08 ` [PATCH 1/2] " Haitao Huang
2023-07-18 1:08 ` [PATCH 2/2] cgroup/misc: Change counters to be explicit 64bit types Haitao Huang
2023-07-18 22:52 ` Tejun Heo
2023-07-21 2:48 ` Haitao Huang
2023-07-21 12:02 ` [PATCH] cgroup/misc: Store atomic64_t reads to u64 Haitao Huang
2023-07-21 18:10 ` Tejun Heo
2023-07-18 1:11 ` [PATCH] cgroup/misc: Fix an overflow Haitao Huang
2023-07-18 15:41 ` Jarkko Sakkinen
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