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Commit f409adf5b1db55ece7e80b67a944f9c0d3fe93e9

Authored by Thomas Gleixner
1 parent 2b876f95d0
Exists in master and in 39 other branches 8mp-imx_5.4.70_2.3.0, 8qm-imx_5.4.70_2.3.0, emb_imx_lf-5.15.y, emb_lf-6.1.y, imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, imx_4.1.15_1.0.0_ga, pitx_8mp_lf-5.10.y, rt-smarc-imx_4.1.15_1.0.0_ga, rt_linux_5.15.71, smarc-8m-android-11.0.0_2.0.0, smarc-imx6_4.14.98_2.0.0_ga, smarc-imx6_4.9.88_2.0.0_ga, smarc-imx7_4.14.98_2.0.0_ga, smarc-imx7_4.9.11_1.0.0_ga, smarc-imx7_4.9.88_2.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-imx_4.1.15_1.0.0_ga, smarc-imx_4.9.11_1.0.0_ga, smarc-imx_4.9.51_imx8m_ga, smarc-imx_4.9.88_2.0.0_ga, smarc-m6.0.1_2.1.0-ga, smarc-n7.1.2_2.0.0-ga, smarc-rel_imx_4.1.15_1.2.0_ga, smarc_8m_00d0_imx_4.14.98_2.0.0_ga, smarc_8m_imx_4.14.78_1.0.0_ga, smarc_8m_imx_4.14.98_2.0.0_ga, smarc_8m_imx_4.19.35_1.1.0, smarc_8mm_imx_4.14.78_1.0.0_ga, smarc_8mm_imx_4.14.98_2.0.0_ga, smarc_8mm_imx_4.19.35_1.1.0, smarc_8mm_imx_5.4.24_2.1.0, smarc_8mp_lf-5.10.y, smarc_8mq_imx_5.4.24_2.1.0, smarc_8mq_lf-5.10.y, smarc_imx_lf-5.15.y

futex: Protect pid lookup in compat code with RCU 

find_task_by_vpid() in compat_sys_get_robust_list() does not require
tasklist_lock. It can be protected with rcu_read_lock as done in
sys_get_robust_list() already.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Darren Hart <dvhltc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>

Showing 1 changed file with 3 additions and 3 deletions Side-by-side Diff

kernel/futex_compat.c
Diff comments   View file @ f409adf
... ... @@ -146,7 +146,7 @@
146 146 struct task_struct *p;
147 147  
148 148 ret = -ESRCH;
149   - read_lock(&tasklist_lock);
  149 + rcu_read_lock();
150 150 p = find_task_by_vpid(pid);
151 151 if (!p)
152 152 goto err_unlock;
... ... @@ -157,7 +157,7 @@
157 157 !capable(CAP_SYS_PTRACE))
158 158 goto err_unlock;
159 159 head = p->compat_robust_list;
160   - read_unlock(&tasklist_lock);
  160 + rcu_read_unlock();
161 161 }
162 162  
163 163 if (put_user(sizeof(*head), len_ptr))
... ... @@ -165,7 +165,7 @@
165 165 return put_user(ptr_to_compat(head), head_ptr);
166 166  
167 167 err_unlock:
168   - read_unlock(&tasklist_lock);
  168 + rcu_read_unlock();
169 169  
170 170 return ret;
171 171 }