From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net
Cc: netdev@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [BUG] bpf: syscall: a possible sleep-in-atomic-context bug in map_update_elem()
Date: Fri, 10 Aug 2018 22:07:23 +0800 [thread overview]
Message-ID: <65830741-bf35-4d32-e365-c32fc17c25cb@gmail.com> (raw)
The kernel may sleep with holding a rcu read lock.
The function call paths (from bottom to top) in Linux-4.16 are:
[FUNC] kmalloc(GFP_KERNEL)
kernel/kthread.c, 283: kmalloc in __kthread_create_on_node
kernel/kthread.c, 365: __kthread_create_on_node in kthread_create_on_node
kernel/bpf/cpumap.c, 368: kthread_create_on_node in __cpu_map_entry_alloc
kernel/bpf/cpumap.c, 490: __cpu_map_entry_alloc in cpu_map_update_elem
kernel/bpf/syscall.c, 724: [FUNC_PTR]cpu_map_update_elem in map_update_elem
kernel/bpf/syscall.c, 723: rcu_read_lock in map_update_elem
Note that [FUNC_PTR] means a function pointer call is used.
I do not find a good way to fix it, so I only report.
This is found by my static analysis tool (DSAC).
Best wishes,
Jia-Ju Bai
next reply other threads:[~2018-08-10 14:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-10 14:07 Jia-Ju Bai [this message]
2018-08-10 14:22 ` [BUG] bpf: syscall: a possible sleep-in-atomic-context bug in map_update_elem() Daniel Borkmann
2018-08-11 1:57 ` Jia-Ju Bai
2018-08-11 5:01 ` Y Song
2018-08-13 2:48 ` Jia-Ju Bai
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