Subject: + coredump-kill-call_count-add-core_name_size.patch added to -mm tree To: oleg@xxxxxxxxxx,andi@xxxxxxxxxxxxxx,jslaby@xxxxxxx,lucas.de.marchi@xxxxxxxxx,mzxreary@xxxxxxxxxxx,nhorman@xxxxxxxxxxxxx,vda.linux@xxxxxxxxxxxxxx,walters@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Fri, 24 May 2013 12:53:47 -0700 The patch titled Subject: coredump: kill call_count, add core_name_size has been added to the -mm tree. Its filename is coredump-kill-call_count-add-core_name_size.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Oleg Nesterov <oleg@xxxxxxxxxx> Subject: coredump: kill call_count, add core_name_size Imho, "atomic_t call_count" is ugly and should die. It buys nothing and in fact it can grow more than necessary, expand doesn't check if it was already incremented by another task. Kill it, and introduce "static int core_name_size" updated by expand_corename(). This is obviously racy too but harmless, and core_name_size never grows for no reason. We do not bother to to calculate the "right" new size, we simply do kmalloc(size_we_need) and use ksize() to rely on kmalloc_index's decision. Finally change format_corename() to use expand_corename(), krealloc(NULL) is fine. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Andi Kleen <andi@xxxxxxxxxxxxxx> Cc: Colin Walters <walters@xxxxxxxxxx> Cc: Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx> Cc: Jiri Slaby <jslaby@xxxxxxx> Cc: Lennart Poettering <mzxreary@xxxxxxxxxxx> Cc: Lucas De Marchi <lucas.de.marchi@xxxxxxxxx> Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/coredump.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff -puN fs/coredump.c~coredump-kill-call_count-add-core_name_size fs/coredump.c --- a/fs/coredump.c~coredump-kill-call_count-add-core_name_size +++ a/fs/coredump.c @@ -45,26 +45,28 @@ #include <trace/events/sched.h> int core_uses_pid; -char core_pattern[CORENAME_MAX_SIZE] = "core"; unsigned int core_pipe_limit; +char core_pattern[CORENAME_MAX_SIZE] = "core"; +static int core_name_size = CORENAME_MAX_SIZE; struct core_name { char *corename; int used, size; }; -static atomic_t call_count = ATOMIC_INIT(1); /* The maximal length of core_pattern is also specified in sysctl.c */ -static int expand_corename(struct core_name *cn) +static int expand_corename(struct core_name *cn, int size) { - int size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count); char *corename = krealloc(cn->corename, size, GFP_KERNEL); if (!corename) return -ENOMEM; - cn->size = size; + if (size > core_name_size) /* racy but harmless */ + core_name_size = size; + + cn->size = ksize(corename); cn->corename = corename; return 0; } @@ -81,7 +83,7 @@ again: return 0; } - if (!expand_corename(cn)) + if (!expand_corename(cn, cn->size + need - free + 1)) goto again; return -ENOMEM; @@ -160,9 +162,8 @@ static int format_corename(struct core_n int err = 0; cn->used = 0; - cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count); - cn->corename = kmalloc(cn->size, GFP_KERNEL); - if (!cn->corename) + cn->corename = NULL; + if (expand_corename(cn, core_name_size)) return -ENOMEM; /* Repeat as long as we have more pattern to process and more output _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are origin.patch posix_cpu_timer-consolidate-expiry-time-type.patch posix_cpu_timers-consolidate-timer-list-cleanups.patch posix_cpu_timers-consolidate-expired-timers-check.patch posix-timers-correctly-get-dying-task-time-sample-in-posix_cpu_timer_schedule.patch posix_timers-fix-racy-timer-delta-caching-on-task-exit.patch lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch ptrace-powerpc-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch ptrace-arm-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch ptrace-sh-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch ptrace-revert-prepare-to-fix-racy-accesses-on-task-breakpoints.patch ptrace-x86-simplify-the-disable-logic-in-ptrace_write_dr7.patch ptrace-x86-dont-delay-disable-till-second-pass-in-ptrace_write_dr7.patch ptrace-x86-introduce-ptrace_register_breakpoint.patch ptrace-x86-ptrace_write_dr7-should-create-bp-if-disabled.patch ptrace-x86-cleanup-ptrace_set_debugreg.patch ptrace-ptrace_detach-should-do-flush_ptrace_hw_breakpointchild.patch ptrace-x86-flush_ptrace_hw_breakpoint-shoule-clear-the-virtual-debug-registers.patch x86-kill-tif_debug.patch coredump-format_corename-can-leak-cn-corename.patch coredump-introduce-cn_vprintf.patch coredump-cn_vprintf-has-no-reason-to-call-vsnprintf-twice.patch coredump-kill-cn_escape-introduce-cn_esc_printf.patch coredump-kill-call_count-add-core_name_size.patch coredump-%-at-the-end-shouldnt-bypass-core_uses_pid-logic.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