The patch titled kexec: fix hang on i386 when panic occurs while console_sem is held has been removed from the -mm tree. Its filename was kexec-fix-hang-on-i386-when-panic-occurs-while-console_sem-is-held.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: kexec: fix hang on i386 when panic occurs while console_sem is held From: Neil Horman <nhorman@xxxxxxxxxxxxx> There is a corner case in 32 bit x86 kdump at the moment. When the box panics via nmi, we call bust_spinlocks(1) to disable sensitivity to the console_sem (allowing us to print to the console in all cases), but we don't call crash_kexec, until after we call bust_spinlocks(0), which re-enables console_sem sensitivity. The result is that, if we get an nmi while the console_sem is held and kdump is configured, and we try to print something to the console during kdump shutdown (which we often do) we deadlock the box. The fix is to simply do what 64 bit die_nmi does which is to not call bust_spinlocks(0) until after we call crash_kexec. Signed-off-by: Neil Horman <nhorman@xxxxxxxxxxxxx> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/dumpstack_32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN arch/x86/kernel/dumpstack_32.c~kexec-fix-hang-on-i386-when-panic-occurs-while-console_sem-is-held arch/x86/kernel/dumpstack_32.c --- a/arch/x86/kernel/dumpstack_32.c~kexec-fix-hang-on-i386-when-panic-occurs-while-console_sem-is-held +++ a/arch/x86/kernel/dumpstack_32.c @@ -405,7 +405,6 @@ die_nmi(char *str, struct pt_regs *regs, panic("Non maskable interrupt"); console_silent(); spin_unlock(&nmi_print_lock); - bust_spinlocks(0); /* * If we are in kernel we are probably nested up pretty bad @@ -416,6 +415,7 @@ die_nmi(char *str, struct pt_regs *regs, crash_kexec(regs); } + bust_spinlocks(0); do_exit(SIGSEGV); } _ Patches currently in -mm which might be from nhorman@xxxxxxxxxxxxx are linux-next.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html