Christophe Leroy <christophe.le...@csgroup.eu> writes: > Le 30/11/2023 à 13:50, Michael Ellerman a écrit : >> Allow a transition from the softirq stack to the hardirq stack when >> handling a hardirq. Doing so means a hardirq received while deep in >> softirq processing is less likely to cause a stack overflow of the >> softirq stack. >> >> Previously it wasn't safe to do so because irq_exit() (which initiates >> softirq processing) was called on the hardirq stack. >> >> That was changed in commit 1b1b6a6f4cc0 ("powerpc: handle irq_enter/ >> irq_exit in interrupt handler wrappers") and 1346d00e1bdf ("powerpc: >> Don't select HAVE_IRQ_EXIT_ON_IRQ_STACK"). >> >> The allowed transitions are now: >> - process stack -> hardirq stack >> - process stack -> softirq stack >> - process stack -> softirq stack -> hardirq stack > > It means you don't like my patch > https://patchwork.ozlabs.org/project/linuxppc-dev/patch/6cd9d8bb2258d8b51999c2584eac74423d2b5e29.1657203774.git.christophe.le...@csgroup.eu/ > > ?
I did like your patch :) But then we got reports of folks hitting stack overflow in some distro kernels, and in at least some cases it was a hardirq coming in during softirq handling and overflowing the softirq stack. > I never got any feedback. Sorry, not enough hours in the day. cheers