d0e60206be
This patch replaces rcu_deference() with rcu_dereference_bh() in ipv6_route_seq_next() to avoid the following warning: [ 19.431685] WARNING: suspicious RCU usage [ 19.433451] 4.14.0-rc3-00914-g66f5d6c #118 Not tainted [ 19.435509] ----------------------------- [ 19.437267] net/ipv6/ip6_fib.c:2259 suspicious rcu_dereference_check() usage! [ 19.440790] [ 19.440790] other info that might help us debug this: [ 19.440790] [ 19.444734] [ 19.444734] rcu_scheduler_active = 2, debug_locks = 1 [ 19.447757] 2 locks held by odhcpd/3720: [ 19.449480] #0: (&p->lock){+.+.}, at: [<ffffffffb1231f7d>] seq_read+0x3c/0x333 [ 19.452720] #1: (rcu_read_lock_bh){....}, at: [<ffffffffb1d2b984>] ipv6_route_seq_start+0x5/0xfd [ 19.456323] [ 19.456323] stack backtrace: [ 19.458812] CPU: 0 PID: 3720 Comm: odhcpd Not tainted 4.14.0-rc3-00914-g66f5d6c #118 [ 19.462042] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 19.465414] Call Trace: [ 19.466788] dump_stack+0x86/0xc0 [ 19.468358] lockdep_rcu_suspicious+0xea/0xf3 [ 19.470183] ipv6_route_seq_next+0x71/0x164 [ 19.471963] seq_read+0x244/0x333 [ 19.473522] proc_reg_read+0x48/0x67 [ 19.475152] ? proc_reg_write+0x67/0x67 [ 19.476862] __vfs_read+0x26/0x10b [ 19.478463] ? __might_fault+0x37/0x84 [ 19.480148] vfs_read+0xba/0x146 [ 19.481690] SyS_read+0x51/0x8e [ 19.483197] do_int80_syscall_32+0x66/0x15a [ 19.484969] entry_INT80_compat+0x32/0x50 [ 19.486707] RIP: 0023:0xf7f0be8e [ 19.488244] RSP: 002b:00000000ffa75d04 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 19.491431] RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 0000000008056068 [ 19.493886] RDX: 0000000000001000 RSI: 0000000008056008 RDI: 0000000000001000 [ 19.496331] RBP: 00000000000001ff R08: 0000000000000000 R09: 0000000000000000 [ 19.498768] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 19.501217] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Fixes: 66f5d6ce53e6 ("ipv6: replace rwlock with rcu and spinlock in fib6_table") Reported-by: Xiaolong Ye <xiaolong.ye@intel.com> Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.