April 2024 - Kernel - mailweb.openeuler.org

[openeuler:OLK-6.6 2437/7374] mm/dynamic_pool.c:118:55: sparse: sparse: incorrect type in initializer (different address spaces)
by kernel test robot 12 Apr '24

12 Apr '24

tree: https://gitee.com/openeuler/kernel.git OLK-6.6 head: 8f7c77eb69ee331fb66fad8eec5ca81b8843eaf3 commit: 8822f3476adadcf84c7cb3db0d1a0a39a6fdc398 [2437/7374] mm/dynamic_pool: introduce per-memcg memory pool config: arm64-randconfig-r132-20240412 (https://download.01.org/0day-ci/archive/20240412/202404120329.pEWUfaZU-lkp@…) compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 8b3b4a92adee40483c27f26c478a384cd69c6f05) reproduce: (https://download.01.org/0day-ci/archive/20240412/202404120329.pEWUfaZU-lkp@…) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp(a)intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202404120329.pEWUfaZU-lkp@intel.com/ sparse warnings: (new ones prefixed by >>) >> mm/dynamic_pool.c:118:55: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected struct cgroup_subsys_state *css @@ got struct cgroup_subsys_state [noderef] __rcu * @@ mm/dynamic_pool.c:118:55: sparse: expected struct cgroup_subsys_state *css mm/dynamic_pool.c:118:55: sparse: got struct cgroup_subsys_state [noderef] __rcu * vim +118 mm/dynamic_pool.c 115 116 int dynamic_pool_destroy(struct cgroup *cgrp, bool *clear_css_online) 117 { > 118 struct cgroup_subsys_state *css = cgrp->subsys[memory_cgrp_id]; 119 struct mem_cgroup *memcg = mem_cgroup_from_css(css); 120 struct dynamic_pool *dpool; 121 int ret = 0; 122 123 if (!dpool_enabled || !memcg) 124 return 0; 125 126 mutex_lock(&dpool_mutex); 127 dpool = dpool_get_from_memcg(memcg); 128 if (!dpool) 129 goto unlock; 130 131 if (dpool->memcg != memcg) { 132 memcg->dpool = NULL; 133 goto put; 134 } 135 136 /* A offline dpool is not allowed for allocation */ 137 dpool->online = false; 138 139 memcg->dpool = NULL; 140 141 /* Release the initial reference count */ 142 dpool_put(dpool); 143 144 /* 145 * Since dpool is destroyed and the memcg will be freed then, 146 * clear CSS_ONLINE immediately to prevent race with create. 147 */ 148 if (cgrp->self.flags & CSS_ONLINE) { 149 cgrp->self.flags &= ~CSS_ONLINE; 150 *clear_css_online = true; 151 } 152 153 put: 154 dpool_put(dpool); 155 unlock: 156 mutex_unlock(&dpool_mutex); 157 158 return ret; 159 } 160 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki

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[openeuler:OLK-6.6 1834/7374] mm/page_cache_limit.c:35:5: sparse: sparse: symbol 'cache_reclaim_enable_handler' was not declared. Should it be static?
by kernel test robot 12 Apr '24

12 Apr '24

tree: https://gitee.com/openeuler/kernel.git OLK-6.6 head: 8f7c77eb69ee331fb66fad8eec5ca81b8843eaf3 commit: 621647ce254f1d347ae9bc3d328c09cbb2732487 [1834/7374] mm: support periodical memory reclaim config: x86_64-randconfig-123-20240412 (https://download.01.org/0day-ci/archive/20240412/202404120351.SxZeSfTi-lkp@…) compiler: gcc-9 (Ubuntu 9.5.0-4ubuntu2) 9.5.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240412/202404120351.SxZeSfTi-lkp@…) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp(a)intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202404120351.SxZeSfTi-lkp@intel.com/ sparse warnings: (new ones prefixed by >>) >> mm/page_cache_limit.c:35:5: sparse: sparse: symbol 'cache_reclaim_enable_handler' was not declared. Should it be static? >> mm/page_cache_limit.c:51:5: sparse: sparse: symbol 'cache_reclaim_sysctl_handler' was not declared. Should it be static? vim +/cache_reclaim_enable_handler +35 mm/page_cache_limit.c 34 > 35 int cache_reclaim_enable_handler(struct ctl_table *table, int write, 36 void *buffer, size_t *length, loff_t *ppos) 37 { 38 int ret; 39 40 ret = proc_dointvec_minmax(table, write, buffer, length, ppos); 41 if (ret || !write) 42 return ret; 43 44 if (should_periodical_reclaim()) 45 schedule_delayed_work(&shepherd, round_jiffies_relative( 46 (unsigned long)vm_cache_reclaim_s * HZ)); 47 48 return 0; 49 } 50 > 51 int cache_reclaim_sysctl_handler(struct ctl_table *table, int write, 52 void *buffer, size_t *length, loff_t *ppos) 53 { 54 int ret; 55 56 ret = proc_dointvec_minmax(table, write, buffer, length, ppos); 57 if (ret || !write) 58 return ret; 59 60 if (should_periodical_reclaim()) 61 mod_delayed_work(system_unbound_wq, &shepherd, 62 round_jiffies_relative( 63 (unsigned long)vm_cache_reclaim_s * HZ)); 64 65 return ret; 66 } 67 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki

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[openeuler:OLK-6.6 1657/7374] kernel/sched/fair.c:8325:9: error: implicit declaration of function 'sched_idle_cpu'; did you mean 'sched_idle_rq'?
by kernel test robot 12 Apr '24

12 Apr '24

tree: https://gitee.com/openeuler/kernel.git OLK-6.6 head: 8f7c77eb69ee331fb66fad8eec5ca81b8843eaf3 commit: 926b9b0cd97e640ee680347cf449c3dc152dddd2 [1657/7374] sched: Throttle qos cfs_rq when current cpu is running online task config: x86_64-randconfig-123-20240412 (https://download.01.org/0day-ci/archive/20240412/202404120103.YG6kXg4w-lkp@…) compiler: gcc-9 (Ubuntu 9.5.0-4ubuntu2) 9.5.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240412/202404120103.YG6kXg4w-lkp@…) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp(a)intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202404120103.YG6kXg4w-lkp@intel.com/ All errors (new ones prefixed by >>): In file included from include/linux/export.h:5, from include/linux/linkage.h:7, from include/linux/kernel.h:17, from include/linux/cpumask.h:10, from include/linux/energy_model.h:4, from kernel/sched/fair.c:23: kernel/sched/fair.c: In function 'check_qos_cfs_rq': >> kernel/sched/fair.c:8325:9: error: implicit declaration of function 'sched_idle_cpu'; did you mean 'sched_idle_rq'? [-Werror=implicit-function-declaration] 8325 | !sched_idle_cpu(smp_processor_id()) && | ^~~~~~~~~~~~~~ include/linux/compiler.h:77:42: note: in definition of macro 'unlikely' 77 | # define unlikely(x) __builtin_expect(!!(x), 0) | ^ >> kernel/sched/fair.c:8328:21: error: 'struct rq' has no member named 'online' 8328 | if (!rq_of(cfs_rq)->online) | ^~ kernel/sched/fair.c: In function 'pick_next_task_fair': >> kernel/sched/fair.c:8531:7: error: 'struct rq' has no member named 'idle_stamp'; did you mean 'idle_state'? 8531 | rq->idle_stamp = 0; | ^~~~~~~~~~ | idle_state kernel/sched/fair.c: At top level: kernel/sched/fair.c:8166:13: warning: 'start_qos_hrtimer' used but never defined 8166 | static void start_qos_hrtimer(int cpu); | ^~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +8325 kernel/sched/fair.c 8321 8322 static bool check_qos_cfs_rq(struct cfs_rq *cfs_rq) 8323 { 8324 if (unlikely(cfs_rq && cfs_rq->tg->qos_level < 0 && > 8325 !sched_idle_cpu(smp_processor_id()) && 8326 cfs_rq->h_nr_running == cfs_rq->idle_h_nr_running)) { 8327 > 8328 if (!rq_of(cfs_rq)->online) 8329 return false; 8330 8331 throttle_qos_cfs_rq(cfs_rq); 8332 return true; 8333 } 8334 8335 return false; 8336 } 8337 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki

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[PATCH OLK-5.10] nilfs2: fix potential bug in end_buffer_async_write
by Zizhi Wo 11 Apr '24

11 Apr '24

From: Ryusuke Konishi <konishi.ryusuke(a)gmail.com> stable inclusion from stable-v5.10.210 commit f3e4963566f58726d3265a727116a42b591f6596 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9E2FP CVE: CVE-2024-26685 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 5bc09b397cbf1221f8a8aacb1152650c9195b02b upstream. According to a syzbot report, end_buffer_async_write(), which handles the completion of block device writes, may detect abnormal condition of the buffer async_write flag and cause a BUG_ON failure when using nilfs2. Nilfs2 itself does not use end_buffer_async_write(). But, the async_write flag is now used as a marker by commit 7f42ec394156 ("nilfs2: fix issue with race condition of competition between segments for dirty blocks") as a means of resolving double list insertion of dirty blocks in nilfs_lookup_dirty_data_buffers() and nilfs_lookup_node_buffers() and the resulting crash. This modification is safe as long as it is used for file data and b-tree node blocks where the page caches are independent. However, it was irrelevant and redundant to also introduce async_write for segment summary and super root blocks that share buffers with the backing device. This led to the possibility that the BUG_ON check in end_buffer_async_write would fail as described above, if independent writebacks of the backing device occurred in parallel. The use of async_write for segment summary buffers has already been removed in a previous change. Fix this issue by removing the manipulation of the async_write flag for the remaining super root block buffer. Link: https://lkml.kernel.org/r/20240203161645.4992-1-konishi.ryusuke@gmail.com Fixes: 7f42ec394156 ("nilfs2: fix issue with race condition of competition between segments for dirty blocks") Signed-off-by: Ryusuke Konishi <konishi.ryusuke(a)gmail.com> Reported-by: syzbot+5c04210f7c7f897c1e7f(a)syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/00000000000019a97c05fd42f8c8@google.com Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Zizhi Wo <wozizhi(a)huawei.com> --- fs/nilfs2/segment.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c index 418055ac910b..be0ca35b8aa4 100644 --- a/fs/nilfs2/segment.c +++ b/fs/nilfs2/segment.c @@ -1707,7 +1707,6 @@ static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci) list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { - set_buffer_async_write(bh); if (bh == segbuf->sb_super_root) { if (bh->b_page != bd_page) { lock_page(bd_page); @@ -1718,6 +1717,7 @@ static void nilfs_segctor_prepare_write(struct nilfs_sc_info *sci) } break; } + set_buffer_async_write(bh); if (bh->b_page != fs_page) { nilfs_begin_page_io(fs_page); fs_page = bh->b_page; @@ -1803,7 +1803,6 @@ static void nilfs_abort_logs(struct list_head *logs, int err) list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { - clear_buffer_async_write(bh); if (bh == segbuf->sb_super_root) { clear_buffer_uptodate(bh); if (bh->b_page != bd_page) { @@ -1812,6 +1811,7 @@ static void nilfs_abort_logs(struct list_head *logs, int err) } break; } + clear_buffer_async_write(bh); if (bh->b_page != fs_page) { nilfs_end_page_io(fs_page, err); fs_page = bh->b_page; @@ -1899,8 +1899,9 @@ static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci) BIT(BH_Delay) | BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Redirected)); - set_mask_bits(&bh->b_state, clear_bits, set_bits); if (bh == segbuf->sb_super_root) { + set_buffer_uptodate(bh); + clear_buffer_dirty(bh); if (bh->b_page != bd_page) { end_page_writeback(bd_page); bd_page = bh->b_page; @@ -1908,6 +1909,7 @@ static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci) update_sr = true; break; } + set_mask_bits(&bh->b_state, clear_bits, set_bits); if (bh->b_page != fs_page) { nilfs_end_page_io(fs_page, 0); fs_page = bh->b_page; -- 2.39.2

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[PATCH openEuler-1.0-LTS 0/2] Fix CVE-2024-26685
by Zizhi Wo 11 Apr '24

11 Apr '24

Fixup the CVE-2024-26685 Ryusuke Konishi (2): nilfs2: fix buffer corruption due to concurrent device reads nilfs2: fix potential bug in end_buffer_async_write fs/nilfs2/segbuf.c | 6 ++++++ fs/nilfs2/segment.c | 15 ++++++++++++--- fs/nilfs2/super.c | 23 ++++++++++++++++++++++- 3 files changed, 40 insertions(+), 4 deletions(-) -- 2.39.2

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[PATCH OLK-5.10 0/2] Fix CVE-2024-26685
by Zizhi Wo 11 Apr '24

11 Apr '24

Fix up the CVE-2024-26685 Ryusuke Konishi (2): nilfs2: fix buffer corruption due to concurrent device reads nilfs2: fix potential bug in end_buffer_async_write fs/nilfs2/segbuf.c | 6 ++++++ fs/nilfs2/segment.c | 15 ++++++++++++--- fs/nilfs2/super.c | 23 ++++++++++++++++++++++- 3 files changed, 40 insertions(+), 4 deletions(-) -- 2.39.2

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[PATCH OLK-5.10] ceph: prevent use-after-free in encode_cap_msg()
by Long Li 11 Apr '24

11 Apr '24

From: Rishabh Dave <ridave(a)redhat.com> stable inclusion from stable-v5.10.167 commit 8180d0c27b93a6eb60da1b08ea079e3926328214 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9E2GN CVE: CVE-2024-26689 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=… -------------------------------- commit cda4672da1c26835dcbd7aec2bfed954eda9b5ef upstream. In fs/ceph/caps.c, in encode_cap_msg(), "use after free" error was caught by KASAN at this line - 'ceph_buffer_get(arg->xattr_buf);'. This implies before the refcount could be increment here, it was freed. In same file, in "handle_cap_grant()" refcount is decremented by this line - 'ceph_buffer_put(ci->i_xattrs.blob);'. It appears that a race occurred and resource was freed by the latter line before the former line could increment it. encode_cap_msg() is called by __send_cap() and __send_cap() is called by ceph_check_caps() after calling __prep_cap(). __prep_cap() is where arg->xattr_buf is assigned to ci->i_xattrs.blob. This is the spot where the refcount must be increased to prevent "use after free" error. Cc: stable(a)vger.kernel.org Link: https://tracker.ceph.com/issues/59259 Signed-off-by: Rishabh Dave <ridave(a)redhat.com> Reviewed-by: Jeff Layton <jlayton(a)kernel.org> Reviewed-by: Xiubo Li <xiubli(a)redhat.com> Signed-off-by: Ilya Dryomov <idryomov(a)gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Long Li <leo.lilong(a)huawei.com> --- fs/ceph/caps.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index b0cf79b0dc49..8e43d07ffa8b 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -1402,7 +1402,7 @@ static void __prep_cap(struct cap_msg_args *arg, struct ceph_cap *cap, if (flushing & CEPH_CAP_XATTR_EXCL) { arg->old_xattr_buf = __ceph_build_xattrs_blob(ci); arg->xattr_version = ci->i_xattrs.version; - arg->xattr_buf = ci->i_xattrs.blob; + arg->xattr_buf = ceph_buffer_get(ci->i_xattrs.blob); } else { arg->xattr_buf = NULL; arg->old_xattr_buf = NULL; @@ -1468,6 +1468,7 @@ static void __send_cap(struct cap_msg_args *arg, struct ceph_inode_info *ci) encode_cap_msg(msg, arg); ceph_con_send(&arg->session->s_con, msg); ceph_buffer_put(arg->old_xattr_buf); + ceph_buffer_put(arg->xattr_buf); if (arg->wake) wake_up_all(&ci->i_cap_wq); } -- 2.31.1

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[PATCH openEuler-1.0-LTS] [Backport] rcu-tasks: Eliminate deadlocks involving do_exit() and RCU tasks
by Liu Chuang 11 Apr '24

11 Apr '24

From: "Paul E. McKenney" <paulmck(a)kernel.org> maillist inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9FXM5 Reference: https://lore.kernel.org/all/20240207110846.25168-1-qiang.zhang1211@gmail.co… -------------------------------- commit bc31e6cb27a9334140ff2f0a209d59b08bc0bc8c upstream. Holding a mutex across synchronize_rcu_tasks() and acquiring that same mutex in code called from do_exit() after its call to exit_tasks_rcu_start() but before its call to exit_tasks_rcu_stop() results in deadlock. This is by design, because tasks that are far enough into do_exit() are no longer present on the tasks list, making it a bit difficult for RCU Tasks to find them, let alone wait on them to do a voluntary context switch. However, such deadlocks are becoming more frequent. In addition, lockdep currently does not detect such deadlocks and they can be difficult to reproduce. In addition, if a task voluntarily context switches during that time (for example, if it blocks acquiring a mutex), then this task is in an RCU Tasks quiescent state. And with some adjustments, RCU Tasks could just as well take advantage of that fact. This commit therefore eliminates these deadlock by replacing the SRCU-based wait for do_exit() completion with per-CPU lists of tasks currently exiting. A given task will be on one of these per-CPU lists for the same period of time that this task would previously have been in the previous SRCU read-side critical section. These lists enable RCU Tasks to find the tasks that have already been removed from the tasks list, but that must nevertheless be waited upon. The RCU Tasks grace period gathers any of these do_exit() tasks that it must wait on, and adds them to the list of holdouts. Per-CPU locking and get_task_struct() are used to synchronize addition to and removal from these lists. Link: https://lore.kernel.org/all/20240118021842.290665-1-chenzhongjin@huawei.com/ Reported-by: Chen Zhongjin <chenzhongjin(a)huawei.com> Signed-off-by: Paul E. McKenney <paulmck(a)kernel.org> Signed-off-by: Zqiang <qiang.zhang1211(a)gmail.com> --- include/linux/sched.h | 1 + init/init_task.c | 1 + kernel/fork.c | 1 + kernel/rcu/update.c | 65 ++++++++++++++++++++++++++++++------------- 4 files changed, 49 insertions(+), 19 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 8fd8c5b7cdc6..2dff665cc33a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -705,6 +705,7 @@ struct task_struct { u8 rcu_tasks_idx; int rcu_tasks_idle_cpu; struct list_head rcu_tasks_holdout_list; + struct list_head rcu_tasks_exit_list; #endif /* #ifdef CONFIG_TASKS_RCU */ struct sched_info sched_info; diff --git a/init/init_task.c b/init/init_task.c index b312a045f4b9..4bc8502d33d3 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -139,6 +139,7 @@ struct task_struct init_task .rcu_tasks_holdout = false, .rcu_tasks_holdout_list = LIST_HEAD_INIT(init_task.rcu_tasks_holdout_list), .rcu_tasks_idle_cpu = -1, + .rcu_tasks_exit_list = LIST_HEAD_INIT(init_task.rcu_tasks_exit_list), #endif #ifdef CONFIG_CPUSETS .mems_allowed_seq = SEQCNT_ZERO(init_task.mems_allowed_seq), diff --git a/kernel/fork.c b/kernel/fork.c index bfc4534ff116..8c96c517e09e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1711,6 +1711,7 @@ static inline void rcu_copy_process(struct task_struct *p) p->rcu_tasks_holdout = false; INIT_LIST_HEAD(&p->rcu_tasks_holdout_list); p->rcu_tasks_idle_cpu = -1; + INIT_LIST_HEAD(&p->rcu_tasks_exit_list); #endif /* #ifdef CONFIG_TASKS_RCU */ } diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 759ea6881a58..af9a43172d0e 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -527,7 +527,8 @@ static DECLARE_WAIT_QUEUE_HEAD(rcu_tasks_cbs_wq); static DEFINE_RAW_SPINLOCK(rcu_tasks_cbs_lock); /* Track exiting tasks in order to allow them to be waited for. */ -DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu); +static LIST_HEAD(rtp_exit_list); +static DEFINE_RAW_SPINLOCK(rtp_exit_list_lock); /* Control stall timeouts. Disable with <= 0, otherwise jiffies till stall. */ #define RCU_TASK_STALL_TIMEOUT (HZ * 60 * 10) @@ -661,6 +662,17 @@ static void check_holdout_task(struct task_struct *t, sched_show_task(t); } +static void rcu_tasks_pertask(struct task_struct *t, struct list_head *hop) +{ + if (t != current && READ_ONCE(t->on_rq) && + !is_idle_task(t)) { + get_task_struct(t); + t->rcu_tasks_nvcsw = READ_ONCE(t->nvcsw); + WRITE_ONCE(t->rcu_tasks_holdout, true); + list_add(&t->rcu_tasks_holdout_list, hop); + } +} + /* RCU-tasks kthread that detects grace periods and invokes callbacks. */ static int __noreturn rcu_tasks_kthread(void *arg) { @@ -726,14 +738,7 @@ static int __noreturn rcu_tasks_kthread(void *arg) */ rcu_read_lock(); for_each_process_thread(g, t) { - if (t != current && READ_ONCE(t->on_rq) && - !is_idle_task(t)) { - get_task_struct(t); - t->rcu_tasks_nvcsw = READ_ONCE(t->nvcsw); - WRITE_ONCE(t->rcu_tasks_holdout, true); - list_add(&t->rcu_tasks_holdout_list, - &rcu_tasks_holdouts); - } + rcu_tasks_pertask(t, &rcu_tasks_holdouts); } rcu_read_unlock(); @@ -744,8 +749,12 @@ static int __noreturn rcu_tasks_kthread(void *arg) * where they have disabled preemption, allowing the * later synchronize_sched() to finish the job. */ - synchronize_srcu(&tasks_rcu_exit_srcu); - + raw_spin_lock_irqsave(&rtp_exit_list_lock, flags); + list_for_each_entry(t, &rtp_exit_list, rcu_tasks_exit_list) { + if (list_empty(&t->rcu_tasks_holdout_list)) + rcu_tasks_pertask(t, &rcu_tasks_holdouts); + } + raw_spin_unlock_irqrestore(&rtp_exit_list_lock, flags); /* * Each pass through the following loop scans the list * of holdout tasks, removing any that are no longer @@ -802,8 +811,7 @@ static int __noreturn rcu_tasks_kthread(void *arg) * * In addition, this synchronize_sched() waits for exiting * tasks to complete their final preempt_disable() region - * of execution, cleaning up after the synchronize_srcu() - * above. + * of execution. */ synchronize_sched(); @@ -835,20 +843,39 @@ static int __init rcu_spawn_tasks_kthread(void) } core_initcall(rcu_spawn_tasks_kthread); -/* Do the srcu_read_lock() for the above synchronize_srcu(). */ +/* + * Protect against tasklist scan blind spot while the task is exiting and + * may be removed from the tasklist. Do this by adding the task to yet + * another list. + */ void exit_tasks_rcu_start(void) { + unsigned long flags; + struct task_struct *t = current; + + WARN_ON_ONCE(!list_empty(&t->rcu_tasks_exit_list)); + get_task_struct(t); preempt_disable(); - current->rcu_tasks_idx = __srcu_read_lock(&tasks_rcu_exit_srcu); + raw_spin_lock_irqsave(&rtp_exit_list_lock, flags); + list_add(&t->rcu_tasks_exit_list, &rtp_exit_list); + raw_spin_unlock_irqrestore(&rtp_exit_list_lock, flags); preempt_enable(); } -/* Do the srcu_read_unlock() for the above synchronize_srcu(). */ +/* + * Remove the task from the "yet another list" because do_exit() is now + * non-preemptible, allowing synchronize_rcu() to wait beyond this point. + */ void exit_tasks_rcu_finish(void) { - preempt_disable(); - __srcu_read_unlock(&tasks_rcu_exit_srcu, current->rcu_tasks_idx); - preempt_enable(); + unsigned long flags; + struct task_struct *t = current; + + WARN_ON_ONCE(list_empty(&t->rcu_tasks_exit_list)); + raw_spin_lock_irqsave(&rtp_exit_list_lock, flags); + list_del_init(&t->rcu_tasks_exit_list); + raw_spin_unlock_irqrestore(&rtp_exit_list_lock, flags); + put_task_struct(t); } #endif /* #ifdef CONFIG_TASKS_RCU */ -- 2.34.1

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[PATCH openEuler-1.0-LTS] [Backport] rcu-tasks: Eliminate deadlocks involving do_exit() and RCU tasks
by Liu Chuang 11 Apr '24

11 Apr '24

From: "Paul E. McKenney" <paulmck(a)kernel.org> maillist inclusion category: bugfix bugzilla: 189584 Reference: https://lore.kernel.org/all/20240207110846.25168-1-qiang.zhang1211@gmail.co… -------------------------------- commit bc31e6cb27a9334140ff2f0a209d59b08bc0bc8c upstream. Holding a mutex across synchronize_rcu_tasks() and acquiring that same mutex in code called from do_exit() after its call to exit_tasks_rcu_start() but before its call to exit_tasks_rcu_stop() results in deadlock. This is by design, because tasks that are far enough into do_exit() are no longer present on the tasks list, making it a bit difficult for RCU Tasks to find them, let alone wait on them to do a voluntary context switch. However, such deadlocks are becoming more frequent. In addition, lockdep currently does not detect such deadlocks and they can be difficult to reproduce. In addition, if a task voluntarily context switches during that time (for example, if it blocks acquiring a mutex), then this task is in an RCU Tasks quiescent state. And with some adjustments, RCU Tasks could just as well take advantage of that fact. This commit therefore eliminates these deadlock by replacing the SRCU-based wait for do_exit() completion with per-CPU lists of tasks currently exiting. A given task will be on one of these per-CPU lists for the same period of time that this task would previously have been in the previous SRCU read-side critical section. These lists enable RCU Tasks to find the tasks that have already been removed from the tasks list, but that must nevertheless be waited upon. The RCU Tasks grace period gathers any of these do_exit() tasks that it must wait on, and adds them to the list of holdouts. Per-CPU locking and get_task_struct() are used to synchronize addition to and removal from these lists. Link: https://lore.kernel.org/all/20240118021842.290665-1-chenzhongjin@huawei.com/ Reported-by: Chen Zhongjin <chenzhongjin(a)huawei.com> Signed-off-by: Paul E. McKenney <paulmck(a)kernel.org> Signed-off-by: Zqiang <qiang.zhang1211(a)gmail.com> --- include/linux/sched.h | 1 + init/init_task.c | 1 + kernel/fork.c | 1 + kernel/rcu/update.c | 65 ++++++++++++++++++++++++++++++------------- 4 files changed, 49 insertions(+), 19 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 8fd8c5b7cdc6..2dff665cc33a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -705,6 +705,7 @@ struct task_struct { u8 rcu_tasks_idx; int rcu_tasks_idle_cpu; struct list_head rcu_tasks_holdout_list; + struct list_head rcu_tasks_exit_list; #endif /* #ifdef CONFIG_TASKS_RCU */ struct sched_info sched_info; diff --git a/init/init_task.c b/init/init_task.c index b312a045f4b9..4bc8502d33d3 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -139,6 +139,7 @@ struct task_struct init_task .rcu_tasks_holdout = false, .rcu_tasks_holdout_list = LIST_HEAD_INIT(init_task.rcu_tasks_holdout_list), .rcu_tasks_idle_cpu = -1, + .rcu_tasks_exit_list = LIST_HEAD_INIT(init_task.rcu_tasks_exit_list), #endif #ifdef CONFIG_CPUSETS .mems_allowed_seq = SEQCNT_ZERO(init_task.mems_allowed_seq), diff --git a/kernel/fork.c b/kernel/fork.c index bfc4534ff116..8c96c517e09e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1711,6 +1711,7 @@ static inline void rcu_copy_process(struct task_struct *p) p->rcu_tasks_holdout = false; INIT_LIST_HEAD(&p->rcu_tasks_holdout_list); p->rcu_tasks_idle_cpu = -1; + INIT_LIST_HEAD(&p->rcu_tasks_exit_list); #endif /* #ifdef CONFIG_TASKS_RCU */ } diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 759ea6881a58..af9a43172d0e 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -527,7 +527,8 @@ static DECLARE_WAIT_QUEUE_HEAD(rcu_tasks_cbs_wq); static DEFINE_RAW_SPINLOCK(rcu_tasks_cbs_lock); /* Track exiting tasks in order to allow them to be waited for. */ -DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu); +static LIST_HEAD(rtp_exit_list); +static DEFINE_RAW_SPINLOCK(rtp_exit_list_lock); /* Control stall timeouts. Disable with <= 0, otherwise jiffies till stall. */ #define RCU_TASK_STALL_TIMEOUT (HZ * 60 * 10) @@ -661,6 +662,17 @@ static void check_holdout_task(struct task_struct *t, sched_show_task(t); } +static void rcu_tasks_pertask(struct task_struct *t, struct list_head *hop) +{ + if (t != current && READ_ONCE(t->on_rq) && + !is_idle_task(t)) { + get_task_struct(t); + t->rcu_tasks_nvcsw = READ_ONCE(t->nvcsw); + WRITE_ONCE(t->rcu_tasks_holdout, true); + list_add(&t->rcu_tasks_holdout_list, hop); + } +} + /* RCU-tasks kthread that detects grace periods and invokes callbacks. */ static int __noreturn rcu_tasks_kthread(void *arg) { @@ -726,14 +738,7 @@ static int __noreturn rcu_tasks_kthread(void *arg) */ rcu_read_lock(); for_each_process_thread(g, t) { - if (t != current && READ_ONCE(t->on_rq) && - !is_idle_task(t)) { - get_task_struct(t); - t->rcu_tasks_nvcsw = READ_ONCE(t->nvcsw); - WRITE_ONCE(t->rcu_tasks_holdout, true); - list_add(&t->rcu_tasks_holdout_list, - &rcu_tasks_holdouts); - } + rcu_tasks_pertask(t, &rcu_tasks_holdouts); } rcu_read_unlock(); @@ -744,8 +749,12 @@ static int __noreturn rcu_tasks_kthread(void *arg) * where they have disabled preemption, allowing the * later synchronize_sched() to finish the job. */ - synchronize_srcu(&tasks_rcu_exit_srcu); - + raw_spin_lock_irqsave(&rtp_exit_list_lock, flags); + list_for_each_entry(t, &rtp_exit_list, rcu_tasks_exit_list) { + if (list_empty(&t->rcu_tasks_holdout_list)) + rcu_tasks_pertask(t, &rcu_tasks_holdouts); + } + raw_spin_unlock_irqrestore(&rtp_exit_list_lock, flags); /* * Each pass through the following loop scans the list * of holdout tasks, removing any that are no longer @@ -802,8 +811,7 @@ static int __noreturn rcu_tasks_kthread(void *arg) * * In addition, this synchronize_sched() waits for exiting * tasks to complete their final preempt_disable() region - * of execution, cleaning up after the synchronize_srcu() - * above. + * of execution. */ synchronize_sched(); @@ -835,20 +843,39 @@ static int __init rcu_spawn_tasks_kthread(void) } core_initcall(rcu_spawn_tasks_kthread); -/* Do the srcu_read_lock() for the above synchronize_srcu(). */ +/* + * Protect against tasklist scan blind spot while the task is exiting and + * may be removed from the tasklist. Do this by adding the task to yet + * another list. + */ void exit_tasks_rcu_start(void) { + unsigned long flags; + struct task_struct *t = current; + + WARN_ON_ONCE(!list_empty(&t->rcu_tasks_exit_list)); + get_task_struct(t); preempt_disable(); - current->rcu_tasks_idx = __srcu_read_lock(&tasks_rcu_exit_srcu); + raw_spin_lock_irqsave(&rtp_exit_list_lock, flags); + list_add(&t->rcu_tasks_exit_list, &rtp_exit_list); + raw_spin_unlock_irqrestore(&rtp_exit_list_lock, flags); preempt_enable(); } -/* Do the srcu_read_unlock() for the above synchronize_srcu(). */ +/* + * Remove the task from the "yet another list" because do_exit() is now + * non-preemptible, allowing synchronize_rcu() to wait beyond this point. + */ void exit_tasks_rcu_finish(void) { - preempt_disable(); - __srcu_read_unlock(&tasks_rcu_exit_srcu, current->rcu_tasks_idx); - preempt_enable(); + unsigned long flags; + struct task_struct *t = current; + + WARN_ON_ONCE(list_empty(&t->rcu_tasks_exit_list)); + raw_spin_lock_irqsave(&rtp_exit_list_lock, flags); + list_del_init(&t->rcu_tasks_exit_list); + raw_spin_unlock_irqrestore(&rtp_exit_list_lock, flags); + put_task_struct(t); } #endif /* #ifdef CONFIG_TASKS_RCU */ -- 2.34.1

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[PATCH OLK-5.10] net/sched: act_mirred: use the backlog for mirred ingress
by Zhengchao Shao 11 Apr '24

11 Apr '24

From: Jakub Kicinski <kuba(a)kernel.org> mainline inclusion from mainline-v6.8-rc6 commit 52f671db18823089a02f07efc04efdb2272ddc17 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9E2LT CVE: CVE-2024-26740 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- The test Davide added in commit ca22da2fbd69 ("act_mirred: use the backlog for nested calls to mirred ingress") hangs our testing VMs every 10 or so runs, with the familiar tcp_v4_rcv -> tcp_v4_rcv deadlock reported by lockdep. The problem as previously described by Davide (see Link) is that if we reverse flow of traffic with the redirect (egress -> ingress) we may reach the same socket which generated the packet. And we may still be holding its socket lock. The common solution to such deadlocks is to put the packet in the Rx backlog, rather than run the Rx path inline. Do that for all egress -> ingress reversals, not just once we started to nest mirred calls. In the past there was a concern that the backlog indirection will lead to loss of error reporting / less accurate stats. But the current workaround does not seem to address the issue. Fixes: 53592b364001 ("net/sched: act_mirred: Implement ingress actions") Cc: Marcelo Ricardo Leitner <marcelo.leitner(a)gmail.com> Suggested-by: Davide Caratti <dcaratti(a)redhat.com> Link: https://lore.kernel.org/netdev/33dc43f587ec1388ba456b4915c75f02a8aae226.166… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> Acked-by: Jamal Hadi Salim <jhs(a)mojatatu.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> Conflicts: net/sched/act_mirred.c Signed-off-by: Zhengchao Shao <shaozhengchao(a)huawei.com> --- net/sched/act_mirred.c | 14 +++++--------- .../testing/selftests/net/forwarding/tc_actions.sh | 3 --- 2 files changed, 5 insertions(+), 12 deletions(-) diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c index 91a19460cb57..66c9f356a876 100644 --- a/net/sched/act_mirred.c +++ b/net/sched/act_mirred.c @@ -206,18 +206,14 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla, return err; } -static bool is_mirred_nested(void) -{ - return unlikely(__this_cpu_read(mirred_nest_level) > 1); -} - -static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb) +static int +tcf_mirred_forward(bool at_ingress, bool want_ingress, struct sk_buff *skb) { int err; if (!want_ingress) err = dev_queue_xmit(skb); - else if (is_mirred_nested()) + else if (!at_ingress) err = netif_rx(skb); else err = netif_receive_skb(skb); @@ -314,7 +310,7 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a, /* let's the caller reinsert the packet, if possible */ if (use_reinsert) { res->ingress = want_ingress; - err = tcf_mirred_forward(res->ingress, skb); + err = tcf_mirred_forward(at_ingress, res->ingress, skb); if (err) tcf_action_inc_overlimit_qstats(&m->common); __this_cpu_dec(mirred_nest_level); @@ -322,7 +318,7 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a, } } - err = tcf_mirred_forward(want_ingress, skb2); + err = tcf_mirred_forward(at_ingress, want_ingress, skb2); if (err) { out: tcf_action_inc_overlimit_qstats(&m->common); diff --git a/tools/testing/selftests/net/forwarding/tc_actions.sh b/tools/testing/selftests/net/forwarding/tc_actions.sh index e396e24d30e0..d6614faf9fe3 100755 --- a/tools/testing/selftests/net/forwarding/tc_actions.sh +++ b/tools/testing/selftests/net/forwarding/tc_actions.sh @@ -188,9 +188,6 @@ mirred_egress_to_ingress_tcp_test() check_err $? "didn't mirred redirect ICMP" tc_check_packets "dev $h1 ingress" 102 10 check_err $? "didn't drop mirred ICMP" - local overlimits=$(tc_rule_stats_get ${h1} 101 egress .overlimits) - test ${overlimits} = 10 - check_err $? "wrong overlimits, expected 10 got ${overlimits}" tc filter del dev $h1 egress protocol ip pref 100 handle 100 flower tc filter del dev $h1 egress protocol ip pref 101 handle 101 flower -- 2.34.1

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