Skip to content
Snippets Groups Projects
  1. Dec 01, 2018
  2. Nov 30, 2018
    • Steven Rostedt (VMware)'s avatar
      tracing/fgraph: Fix set_graph_function from showing interrupts · 5cf99a0f
      Steven Rostedt (VMware) authored
      
      The tracefs file set_graph_function is used to only function graph functions
      that are listed in that file (or all functions if the file is empty). The
      way this is implemented is that the function graph tracer looks at every
      function, and if the current depth is zero and the function matches
      something in the file then it will trace that function. When other functions
      are called, the depth will be greater than zero (because the original
      function will be at depth zero), and all functions will be traced where the
      depth is greater than zero.
      
      The issue is that when a function is first entered, and the handler that
      checks this logic is called, the depth is set to zero. If an interrupt comes
      in and a function in the interrupt handler is traced, its depth will be
      greater than zero and it will automatically be traced, even if the original
      function was not. But because the logic only looks at depth it may trace
      interrupts when it should not be.
      
      The recent design change of the function graph tracer to fix other bugs
      caused the depth to be zero while the function graph callback handler is
      being called for a longer time, widening the race of this happening. This
      bug was actually there for a longer time, but because the race window was so
      small it seldom happened. The Fixes tag below is for the commit that widen
      the race window, because that commit belongs to a series that will also help
      fix the original bug.
      
      Cc: stable@kernel.org
      Fixes: 39eb456d ("function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack")
      Reported-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
      Tested-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
      Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
      5cf99a0f
    • Zenghui Yu's avatar
      tracepoint: Use __idx instead of idx in DO_TRACE macro to make it unique · 0c7a52e4
      Zenghui Yu authored
      
      After enabling KVM event tracing, almost all of trace_kvm_exit()'s
      printk shows
      
      	"kvm_exit: IRQ: ..."
      
      even if the actual exception_type is NOT IRQ.  More specifically,
      trace_kvm_exit() is defined in virt/kvm/arm/trace.h by TRACE_EVENT.
      
      This slight problem may have existed after commit e6753f23
      ("tracepoint: Make rcuidle tracepoint callers use SRCU"). There are
      two variables in trace_kvm_exit() and __DO_TRACE() which have the
      same name, *idx*. Thus the actual value of *idx* will be overwritten
      when tracing. Fix it by adding a simple prefix.
      
      Cc: Joel Fernandes <joel@joelfernandes.org>
      Cc: Wang Haibin <wanghaibin.wang@huawei.com>
      Cc: linux-trace-devel@vger.kernel.org
      Cc: stable@vger.kernel.org
      Fixes: e6753f23 ("tracepoint: Make rcuidle tracepoint callers use SRCU")
      Reviewed-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
      Signed-off-by: default avatarZenghui Yu <yuzenghui@huawei.com>
      Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
      0c7a52e4
    • David Howells's avatar
      afs: Use d_instantiate() rather than d_add() and don't d_drop() · 73116df7
      David Howells authored
      
      Use d_instantiate() rather than d_add() and don't d_drop() in
      afs_vnode_new_inode().  The dentry shouldn't be removed as it's not
      changing its name.
      
      Reported-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      73116df7
    • David Howells's avatar
      afs: Fix missing net error handling · 4584ae96
      David Howells authored
      
      kAFS can be given certain network errors (EADDRNOTAVAIL, EHOSTDOWN and
      ERFKILL) that it doesn't handle in its server/address rotation algorithms.
      They cause the probing and rotation to abort immediately rather than
      rotating.
      
      Fix this by:
      
       (1) Abstracting out the error prioritisation from the VL and FS rotation
           algorithms into a common function and expand usage into the server
           probing code.
      
           When multiple errors are available, this code selects the one we'd
           prefer to return.
      
       (2) Add handling for EADDRNOTAVAIL, EHOSTDOWN and ERFKILL.
      
      Fixes: 0fafdc9f ("afs: Fix file locking")
      Fixes: 0338747d8454 ("afs: Probe multiple fileservers simultaneously")
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      4584ae96