kernel:the API of k_mem_pool_alloc need try again to -EAGAIN[bug] #6757
Assignees
Labels
Comments
MaureenHelm
added
bug
andyross
pushed a commit
to andyross/zephyr
that referenced
this issue
May 24, 2018
The sys_mem_pool implementation has a subtle error case where it detected a simultaneous allocation after having released the lock, in which case exactly one of the racing allocators will return with -EAGAIN (the other one suceeds of course). I documented this condition at the lower level, but forgot to actually handle it at the k_mem_pool level where we want to retry once before going to sleep, as it doesn't generally represent an empty heap. It got caught by code auditing in: zephyrproject-rtos#6757 (Full disclosure: I tested this by whiteboxing the first failure. I wasn't able to put together a rig to reliably exercise the actual race.) This patch also fixes a noop thinko in the return logic in the same function, which contained: (ret == -EAGAIN) || (ret && ret != -ENOMEM) The first term is needless and implied by the second. Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
nashif
pushed a commit
that referenced
this issue
May 27, 2018
The sys_mem_pool implementation has a subtle error case where it detected a simultaneous allocation after having released the lock, in which case exactly one of the racing allocators will return with -EAGAIN (the other one suceeds of course). I documented this condition at the lower level, but forgot to actually handle it at the k_mem_pool level where we want to retry once before going to sleep, as it doesn't generally represent an empty heap. It got caught by code auditing in: #6757 (Full disclosure: I tested this by whiteboxing the first failure. I wasn't able to put together a rig to reliably exercise the actual race.) This patch also fixes a noop thinko in the return logic in the same function, which contained: (ret == -EAGAIN) || (ret && ret != -ENOMEM) The first term is needless and implied by the second. Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
the API of k_mem_pool_alloc should handle the -EAGAIN which is return value of pool_alloc.
at 271 line in mempool.c comments" -EAGAIN isn't for,propagation to the caller, it's to tell the loop in k_mem_pool_alloc() to try again synchronously."but the k_mem_pool_alloc does not handle loop.
by xuemingxing .xuemingxing@zte.com.cn
The text was updated successfully, but these errors were encountered: