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__rust_probestack test in rust_example.rs is causing a stack overflow #111
Description
The stack size is 8KB, having a local variable of 8KB+32 bytes takes it over the edge.
I have seen failures on debug builds for this, for example, https://github.com/Rust-for-Linux/linux/runs/2107043283?check_suite_focus=true -- it has the following error:
[ 13.127113] Large array has length: 1028
[ 13.131438] BUG: stack guard page was hit at (____ptrval____) (stack is (____ptrval____)..(____ptrval____))
[ 13.131438] kernel stack overflow (double-fault): 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
For now I'm reducing the variable size in #104 to work around this. Please fix if you need it to be bigger to ensure probestack is properly tested.
Activity
alex commentedon Mar 15, 2021
Maybe we should put it in a different test file so that it doesn't disrupt code that's expected to work :-)
ojeda commentedon Mar 15, 2021
Indeed. Reorganizing all the test code is something I will work on, but first I need to finish setting up the "independent CI".
Nevertheless, it is good we are seeing the error in the debug builds, it means debug CI is being useful ;-)
adamrk commentedon Mar 16, 2021
So this was triggered by an upstream merge from #112. Does anyone know why (just trying to understand myself)?
ojeda commentedon Mar 16, 2021
The CI link mentioned by Wedson happened before #112 -- it is not a particular change: the frame size has been growing with the added test cases, which means we are crossing the tipping point now.
Eventually we will move these into proper tests, but for the moment my plan is moving them into individual kernel modules since anyhow I need to clean up all the GitHub-only bits (which include
rust_example.rs) to be able to get into linux-next properly.adamrk commentedon Mar 16, 2021
Got it, thanks!
[-]__rust_probestack test in rust_example.rs is causing a stack overflow[/-][+]`__rust_probestack` test in `rust_example.rs` is causing a stack overflow[/+]net/smc: fix kernel panic caused by race of smc_sock
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