Remove O_DIRECT from basic_read_test #114
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This test is failing sporadically in CI with corrupt data. I believe the cause is the same as #84. Per the man page for `open(2)`, `O_DIRECT` is not safe to use concurrently with `fork` syscalls: > O_DIRECT I/Os should never be run concurrently with the fork(2) > system call, if the memory buffer is a private mapping (i.e., any > mapping created with the mmap(2) MAP_PRIVATE flag; this includes > memory allocated on the heap and statically allocated buffers). > Any such I/Os, whether submitted via an asynchronous I/O > interface or from another thread in the process, should be > completed before fork(2) is called. Failure to do so can result > in data corruption and undefined behavior in parent and child > processes. Our test runner does a `fork` every time we mount a FUSE file system, since we don't run our tests as root, and so we need to execute the `fusermount3` utility to do the mount. Since tests run concurrently, that means we will sometimes do one of these forks at the same time as this test is doing an `O_DIRECT` read. Signed-off-by: James Bornholt <bornholt@cs.utexas.edu>
dannycjones
approved these changes
Feb 24, 2023
monthonk
approved these changes
Feb 24, 2023
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This test is failing sporadically in CI with corrupt data. I believe the cause is the same as why we reverted #84. Per the man page for
open(2),O_DIRECTis not safe to use concurrently withforksyscalls:Our test runner does a
forkevery time we mount a FUSE file system, since we don't run our tests as root, and so we need to execute thefusermount3utility to do the mount. Since tests run concurrently, that means we will sometimes do one of these forks at the same time as this test is doing anO_DIRECTread.By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.