The patch titled um: fix crashes, clean up os_dump_core() has been removed from the -mm tree. Its filename was um-os_dump_core-cleanup.patch This patch was dropped because an updated version will be merged The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: um: fix crashes, clean up os_dump_core() From: Richard Weinberger <richard@xxxxxx> When os_dump_core() raises SIGTERM to bring down all UML processes this would also trigger the quite complex do_uml_exitcalls() routine. This is why UML crashed often while panicking. Let's make os_dump_core() short and painless by killing all UML processes with SIGHUP and calling the only sane exit call in this context (remove_umid_dir()) by hand. Signed-off-by: Richard Weinberger <richard@xxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/um/include/shared/os.h | 1 + arch/um/os-Linux/umid.c | 2 +- arch/um/os-Linux/util.c | 22 +++++++--------------- 3 files changed, 9 insertions(+), 16 deletions(-) diff -puN arch/um/include/shared/os.h~um-os_dump_core-cleanup arch/um/include/shared/os.h --- a/arch/um/include/shared/os.h~um-os_dump_core-cleanup +++ a/arch/um/include/shared/os.h @@ -226,6 +226,7 @@ extern int os_get_thread_area(user_desc_ extern int umid_file_name(char *name, char *buf, int len); extern int set_umid(char *name); extern char *get_umid(void); +extern void remove_umid_dir(void); /* signal.c */ extern void timer_init(void); diff -puN arch/um/os-Linux/umid.c~um-os_dump_core-cleanup arch/um/os-Linux/umid.c --- a/arch/um/os-Linux/umid.c~um-os_dump_core-cleanup +++ a/arch/um/os-Linux/umid.c @@ -382,7 +382,7 @@ __uml_setup("uml_dir=", set_uml_dir, " The location to place the pid and umid files.\n\n" ); -static void remove_umid_dir(void) +void remove_umid_dir(void) { char dir[strlen(uml_dir) + UMID_LEN + 1], err; diff -puN arch/um/os-Linux/util.c~um-os_dump_core-cleanup arch/um/os-Linux/util.c --- a/arch/um/os-Linux/util.c~um-os_dump_core-cleanup +++ a/arch/um/os-Linux/util.c @@ -103,30 +103,21 @@ void os_dump_core(void) signal(SIGSEGV, SIG_DFL); /* - * We are about to SIGTERM this entire process group to ensure that - * nothing is around to run after the kernel exits. The - * kernel wants to abort, not die through SIGTERM, so we - * ignore it here. + * Send SIGHUP to kill non-kernel processes, kernel processes + * ignore SIGHUP. + * We are using SIGHUP because it has the same effect as SIGTERM + * but it does not trigger other signal handlers. */ + kill(0, SIGHUP); - signal(SIGTERM, SIG_IGN); - kill(0, SIGTERM); /* * Most of the other processes associated with this UML are * likely sTopped, so give them a SIGCONT so they see the - * SIGTERM. + * SIGHUP. */ kill(0, SIGCONT); /* - * Now, having sent signals to everyone but us, make sure they - * die by ptrace. Processes can survive what's been done to - * them so far - the mechanism I understand is receiving a - * SIGSEGV and segfaulting immediately upon return. There is - * always a SIGSEGV pending, and (I'm guessing) signals are - * processed in numeric order so the SIGTERM (signal 15 vs - * SIGSEGV being signal 11) is never handled. - * * Run a waitpid loop until we get some kind of error. * Hopefully, it's ECHILD, but there's not a lot we can do if * it's something else. Tell os_kill_ptraced_process not to @@ -137,5 +128,6 @@ void os_dump_core(void) while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0) os_kill_ptraced_process(pid, 0); + remove_umid_dir(); uml_abort(); } _ Patches currently in -mm which might be from richard@xxxxxx are origin.patch mm-mmu_gather-rework.patch powerpc-mmu_gather-rework.patch sparc-mmu_gather-rework.patch s390-mmu_gather-rework.patch arm-mmu_gather-rework.patch sh-mmu_gather-rework.patch ia64-mmu_gather-rework.patch um-mmu_gather-rework.patch mm-now-that-all-old-mmu_gather-code-is-gone-remove-the-storage.patch mm-powerpc-move-the-rcu-page-table-freeing-into-generic-code.patch mm-extended-batches-for-generic-mmu_gather.patch lockdep-mutex-provide-mutex_lock_nest_lock.patch mm-remove-i_mmap_lock-lockbreak.patch mm-convert-i_mmap_lock-to-a-mutex.patch mm-revert-page_lock_anon_vma-lock-annotation.patch mm-improve-page_lock_anon_vma-comment.patch mm-use-refcounts-for-page_lock_anon_vma.patch mm-convert-anon_vma-lock-to-a-mutex.patch mm-optimize-page_lock_anon_vma-fast-path.patch um-fix-uml_lib_path.patch um-remove-sighup-handler.patch um-add-earlyprintk-support.patch um-add-ucast-ethernet-transport.patch um-print-info-about-fatal-segfaults.patch um-include-linux-prefetchh.patch um-fix-crash-while-os_dump_core.patch remove-unused-proc_change_penalty-constant.patch lib-consolidate-debug_stack_usage-option.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