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  • Vegard Nossum's avatar
    net/sctp: terminate rhashtable walk correctly · 5fc382d8
    Vegard Nossum authored
    I was seeing a lot of these:
        BUG: sleeping function called from invalid context at mm/slab.h:388
        in_atomic(): 0, irqs_disabled(): 0, pid: 14971, name: trinity-c2
        Preemption disabled at:[<ffffffff819bcd46>] rhashtable_walk_start+0x46/0x150
         [<ffffffff81149abb>] preempt_count_add+0x1fb/0x280
         [<ffffffff83295722>] _raw_spin_lock+0x12/0x40
         [<ffffffff811aac87>] console_unlock+0x2f7/0x930
         [<ffffffff811ab5bb>] vprintk_emit+0x2fb/0x520
         [<ffffffff811aba6a>] vprintk_default+0x1a/0x20
         [<ffffffff812c171a>] printk+0x94/0xb0
         [<ffffffff811d6ed0>] print_stack_trace+0xe0/0x170
         [<ffffffff8115835e>] ___might_sleep+0x3be/0x460
         [<ffffffff81158490>] __might_sleep+0x90/0x1a0
         [<ffffffff8139b823>] kmem_cache_alloc+0x153/0x1e0
         [<ffffffff819bca1e>] rhashtable_walk_init+0xfe/0x2d0
         [<ffffffff82ec64de>] sctp_transport_walk_start+0x1e/0x60
         [<ffffffff82edd8ad>] sctp_transport_seq_start+0x4d/0x150
         [<ffffffff8143a82b>] seq_read+0x27b/0x1180
         [<ffffffff814f97fc>] proc_reg_read+0xbc/0x180
         [<ffffffff813d471b>] __vfs_read+0xdb/0x610
         [<ffffffff813d4d3a>] vfs_read+0xea/0x2d0
         [<ffffffff813d615b>] SyS_pread64+0x11b/0x150
         [<ffffffff8100334c>] do_syscall_64+0x19c/0x410
         [<ffffffff832960a5>] return_from_SYSCALL_64+0x0/0x6a
         [<ffffffffffffffff>] 0xffffffffffffffff
    Apparently we always need to call rhashtable_walk_stop(), even when
    rhashtable_walk_start() fails:
     * rhashtable_walk_start - Start a hash table walk
     * @iter:       Hash table iterator
     * Start a hash table walk.  Note that we take the RCU lock in all
     * cases including when we return an error.  So you must always call
     * rhashtable_walk_stop to clean up.
    otherwise we never call rcu_read_unlock() and we get the splat above.
    Fixes: 53fa1036 ("sctp: fix some rhashtable functions using in sctp proc/diag")
    See-also: 53fa1036 ("sctp: fix some rhashtable functions using in sctp proc/diag")
    See-also: f2dba9c6
     ("rhashtable: Introduce rhashtable_walk_*")
    Cc: Xin Long <>
    Cc: Herbert Xu <>
    Signed-off-by: default avatarVegard Nossum <>
    Acked-by: default avatarMarcelo Ricardo Leitner <>
    Signed-off-by: default avatarDavid S. Miller <>