• Larry Finger's avatar
    mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc() · 8a8c35fa
    Larry Finger authored
    Beginning at commit d52d3997 ("ipv6: Create percpu rt6_info"), the
    following INFO splat is logged:
    
      ===============================
      [ INFO: suspicious RCU usage. ]
      4.1.0-rc7-next-20150612 #1 Not tainted
      -------------------------------
      kernel/sched/core.c:7318 Illegal context switch in RCU-bh read-side critical section!
      other info that might help us debug this:
      rcu_scheduler_active = 1, debug_locks = 0
       3 locks held by systemd/1:
       #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff815f0c8f>] rtnetlink_rcv+0x1f/0x40
       #1:  (rcu_read_lock_bh){......}, at: [<ffffffff816a34e2>] ipv6_add_addr+0x62/0x540
       #2:  (addrconf_hash_lock){+...+.}, at: [<ffffffff816a3604>] ipv6_add_addr+0x184/0x540
      stack backtrace:
      CPU: 0 PID: 1 Comm: systemd Not tainted 4.1.0-rc7-next-20150612 #1
      Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.20   04/17/2014
      Call Trace:
        dump_stack+0x4c/0x6e
        lockdep_rcu_suspicious+0xe7/0x120
        ___might_sleep+0x1d5/0x1f0
        __might_sleep+0x4d/0x90
        kmem_cache_alloc+0x47/0x250
        create_object+0x39/0x2e0
        kmemleak_alloc_percpu+0x61/0xe0
        pcpu_alloc+0x370/0x630
    
    Additional backtrace lines are truncated.  In addition, the above splat
    is followed by several "BUG: sleeping function called from invalid
    context at mm/slub.c:1268" outputs.  As suggested by Martin KaFai Lau,
    these are the clue to the fix.  Routine kmemleak_alloc_percpu() always
    uses GFP_KERNEL for its allocations, whereas it should follow the gfp
    from its callers.
    Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    Reviewed-by: default avatarKamalesh Babulal <kamalesh@linux.vnet.ibm.com>
    Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
    Signed-off-by: default avatarLarry Finger <Larry.Finger@lwfinger.net>
    Cc: Martin KaFai Lau <kafai@fb.com>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Tejun Heo <tj@kernel.org>
    Cc: Christoph Lameter <cl@linux-foundation.org>
    Cc: <stable@vger.kernel.org>	[3.18+]
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    8a8c35fa
kmemleak.c 54.8 KB