Bug 220237 - sys/dev/mlx/mlx.c: A possible sleep-under-mutex bug in mlx_alloccmd
Summary: sys/dev/mlx/mlx.c: A possible sleep-under-mutex bug in mlx_alloccmd
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: CURRENT
Hardware: Any Any
: --- Affects Only Me
Assignee: freebsd-bugs mailing list
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-06-24 03:13 UTC by Jia-Ju Bai
Modified: 2017-06-24 03:13 UTC (History)
0 users

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Description Jia-Ju Bai 2017-06-24 03:13:59 UTC
The driver may sleep under a mutex, and the function call path is:
mlx_attach [line 432: acquire the mutex]
  mlx_enquire
    mlx_alloccmd
      bus_dmamap_create(BUS_DMA_WAITOK) --> may sleep

The possible fix of this bug is to replace the "BUS_DMA_WAITOK" in bus_dmamap_create with "BUS_DMA_NOWAIT".

This bug is found by a static analysis tool written by myself, and it is checked by my review of the FreeBSD code.