From: Tony Luck Date: Wed, 4 Jun 2014 23:10:59 +0000 (-0700) Subject: mm/memory-failure.c-failure: send right signal code to correct thread X-Git-Tag: firefly_0821_release~3679^2~2014 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=4451dd21497254e6f9d28a528bad70cf31a1db91;p=firefly-linux-kernel-4.4.55.git mm/memory-failure.c-failure: send right signal code to correct thread commit a70ffcac741d31a406c1d2b832ae43d658e7e1cf upstream. When a thread in a multi-threaded application hits a machine check because of an uncorrectable error in memory - we want to send the SIGBUS with si.si_code = BUS_MCEERR_AR to that thread. Currently we fail to do that if the active thread is not the primary thread in the process. collect_procs() just finds primary threads and this test: if ((flags & MF_ACTION_REQUIRED) && t == current) { will see that the thread we found isn't the current thread and so send a si.si_code = BUS_MCEERR_AO to the primary (and nothing to the active thread at this time). We can fix this by checking whether "current" shares the same mm with the process that collect_procs() said owned the page. If so, we send the SIGBUS to current (with code BUS_MCEERR_AR). Signed-off-by: Tony Luck Signed-off-by: Naoya Horiguchi Reported-by: Otto Bruggeman Cc: Andi Kleen Cc: Borislav Petkov Cc: Chen Gong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 4f8548abd6ee..bf1b075ff6cf 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -208,9 +208,9 @@ static int kill_proc(struct task_struct *t, unsigned long addr, int trapno, #endif si.si_addr_lsb = compound_trans_order(compound_head(page)) + PAGE_SHIFT; - if ((flags & MF_ACTION_REQUIRED) && t == current) { + if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) { si.si_code = BUS_MCEERR_AR; - ret = force_sig_info(SIGBUS, &si, t); + ret = force_sig_info(SIGBUS, &si, current); } else { /* * Don't use force here, it's convenient if the signal