| Commit message (Collapse) | Author | Age | Files | Lines | |
|---|---|---|---|---|---|
| * | Fix lua stack overflow on recursive call to gsub() | Matthew Ahrens | 2020-07-27 | 1 | -0/+2 |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The `zfs program` subcommand invokes a LUA interpreter to run ZFS "channel programs". This interpreter runs in a constrained environment, with defined memory limits. The LUA stack (used for LUA functions that call each other) is allocated in the kernel's heap, and is limited by the `-m MEMORY-LIMIT` flag and the `zfs_lua_max_memlimit` module parameter. The C stack is used by certain LUA features that are implemented in C. The C stack is limited by `LUAI_MAXCCALLS=20`, which limits call depth. Some LUA C calls use more stack space than others, and `gsub()` uses an unusually large amount. With a programming trick, it can be invoked recursively using the C stack (rather than the LUA stack). This overflows the 16KB Linux kernel stack after about 11 iterations, less than the limit of 20. One solution would be to decrease `LUAI_MAXCCALLS`. This could be made to work, but it has a few drawbacks: 1. The existing test suite does not pass with `LUAI_MAXCCALLS=10`. 2. There may be other LUA functions that use a lot of stack space, and the stack space may change depending on compiler version and options. This commit addresses the problem by adding a new limit on the amount of free space (in bytes) remaining on the C stack while running the LUA interpreter: `LUAI_MINCSTACK=4096`. If there is less than this amount of stack space remaining, a LUA runtime error is generated. Reviewed-by: George Wilson <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Ryan Moeller <[email protected]> Reviewed-by: Allan Jude <[email protected]> Reviewed-by: Serapheim Dimitropoulos <[email protected]> Signed-off-by: Matthew Ahrens <[email protected]> Closes #10611 Closes #10613 | ||||
| * | cppcheck: (error) Address of local auto-variable assigned | Brian Behlendorf | 2019-12-18 | 1 | -0/+1 |
| | | | | | | | | | | | | | Suppress autoVariables warnings in the lua interpreter. The usage here while unconventional in intentional and the same as upstream. [module/lua/ldebug.c:327]: (error) Address of local auto-variable assigned to a function parameter. Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #9732 | ||||
| * | OpenZFS 7431 - ZFS Channel Programs | Chris Williamson | 2018-02-08 | 1 | -0/+606 |
| Authored by: Chris Williamson <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: John Kennedy <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Approved by: Garrett D'Amore <[email protected]> Ported-by: Don Brady <[email protected]> Ported-by: John Kennedy <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7431 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/dfc11533 Porting Notes: * The CLI long option arguments for '-t' and '-m' don't parse on linux * Switched from kmem_alloc to vmem_alloc in zcp_lua_alloc * Lua implementation is built as its own module (zlua.ko) * Lua headers consumed directly by zfs code moved to 'include/sys/lua/' * There is no native setjmp/longjump available in stock Linux kernel. Brought over implementations from illumos and FreeBSD * The get_temporary_prop() was adapted due to VFS platform differences * Use of inline functions in lua parser to reduce stack usage per C call * Skip some ZFS Test Suite ZCP tests on sparc64 to avoid stack overflow | |||||
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