From 1b0df11fde0f14a269a181b3b7f5122415bc5ed7 Mon Sep 17 00:00:00 2001 From: Daniel Jordan Date: Wed, 2 Sep 2020 13:07:56 -0400 Subject: padata: fix possible padata_works_lock deadlock syzbot reports, WARNING: inconsistent lock state 5.9.0-rc2-syzkaller #0 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. syz-executor.0/26715 takes: (padata_works_lock){+.?.}-{2:2}, at: padata_do_parallel kernel/padata.c:220 {IN-SOFTIRQ-W} state was registered at: spin_lock include/linux/spinlock.h:354 [inline] padata_do_parallel kernel/padata.c:220 ... __do_softirq kernel/softirq.c:298 ... sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt arch/x86/include/asm/idtentry.h:581 Possible unsafe locking scenario: CPU0 ---- lock(padata_works_lock); lock(padata_works_lock); padata_do_parallel() takes padata_works_lock with softirqs enabled, so a deadlock is possible if, on the same CPU, the lock is acquired in process context and then softirq handling done in an interrupt leads to the same path. Fix by leaving softirqs disabled while do_parallel holds padata_works_lock. Reported-by: syzbot+f4b9f49e38e25eb4ef52@syzkaller.appspotmail.com Fixes: 4611ce2246889 ("padata: allocate work structures for parallel jobs from a pool") Signed-off-by: Daniel Jordan Cc: Herbert Xu Cc: Steffen Klassert Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Herbert Xu --- kernel/padata.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/padata.c b/kernel/padata.c index 16cb894dc272..d4d3ba6e1728 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -215,12 +215,13 @@ int padata_do_parallel(struct padata_shell *ps, padata->pd = pd; padata->cb_cpu = *cb_cpu; - rcu_read_unlock_bh(); - spin_lock(&padata_works_lock); padata->seq_nr = ++pd->seq_nr; pw = padata_work_alloc(); spin_unlock(&padata_works_lock); + + rcu_read_unlock_bh(); + if (pw) { padata_work_init(pw, padata_parallel_worker, padata, 0); queue_work(pinst->parallel_wq, &pw->pw_work); -- cgit v1.2.3 From a566a9012acd7c9a4be7e30dc7acb7a811ec2260 Mon Sep 17 00:00:00 2001 From: Tycho Andersen Date: Tue, 1 Sep 2020 19:40:16 -0600 Subject: seccomp: don't leak memory when filter install races In seccomp_set_mode_filter() with TSYNC | NEW_LISTENER, we first initialize the listener fd, then check to see if we can actually use it later in seccomp_may_assign_mode(), which can fail if anyone else in our thread group has installed a filter and caused some divergence. If we can't, we partially clean up the newly allocated file: we put the fd, put the file, but don't actually clean up the *memory* that was allocated at filter->notif. Let's clean that up too. To accomplish this, let's hoist the actual "detach a notifier from a filter" code to its own helper out of seccomp_notify_release(), so that in case anyone adds stuff to init_listener(), they only have to add the cleanup code in one spot. This does a bit of extra locking and such on the failure path when the filter is not attached, but it's a slow failure path anyway. Fixes: 51891498f2da ("seccomp: allow TSYNC and USER_NOTIF together") Reported-by: syzbot+3ad9614a12f80994c32e@syzkaller.appspotmail.com Signed-off-by: Tycho Andersen Acked-by: Christian Brauner Link: https://lore.kernel.org/r/20200902014017.934315-1-tycho@tycho.pizza Signed-off-by: Kees Cook --- kernel/seccomp.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 3ee59ce0a323..bb0dd9ae699a 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -1109,13 +1109,12 @@ out: } #ifdef CONFIG_SECCOMP_FILTER -static int seccomp_notify_release(struct inode *inode, struct file *file) +static void seccomp_notify_detach(struct seccomp_filter *filter) { - struct seccomp_filter *filter = file->private_data; struct seccomp_knotif *knotif; if (!filter) - return 0; + return; mutex_lock(&filter->notify_lock); @@ -1142,6 +1141,13 @@ static int seccomp_notify_release(struct inode *inode, struct file *file) kfree(filter->notif); filter->notif = NULL; mutex_unlock(&filter->notify_lock); +} + +static int seccomp_notify_release(struct inode *inode, struct file *file) +{ + struct seccomp_filter *filter = file->private_data; + + seccomp_notify_detach(filter); __put_seccomp_filter(filter); return 0; } @@ -1581,6 +1587,7 @@ out_put_fd: listener_f->private_data = NULL; fput(listener_f); put_unused_fd(listener); + seccomp_notify_detach(prepared); } else { fd_install(listener, listener_f); ret = listener; -- cgit v1.2.3 From e839317900e9f13c83d8711d684de88c625b307a Mon Sep 17 00:00:00 2001 From: Tycho Andersen Date: Wed, 2 Sep 2020 08:09:53 -0600 Subject: seccomp: don't leave dangling ->notif if file allocation fails Christian and Kees both pointed out that this is a bit sloppy to open-code both places, and Christian points out that we leave a dangling pointer to ->notif if file allocation fails. Since we check ->notif for null in order to determine if it's ok to install a filter, this means people won't be able to install a filter if the file allocation fails for some reason, even if they subsequently should be able to. To fix this, let's hoist this free+null into its own little helper and use it. Reported-by: Kees Cook Reported-by: Christian Brauner Signed-off-by: Tycho Andersen Acked-by: Christian Brauner Link: https://lore.kernel.org/r/20200902140953.1201956-1-tycho@tycho.pizza Signed-off-by: Kees Cook --- kernel/seccomp.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/seccomp.c b/kernel/seccomp.c index bb0dd9ae699a..676d4af62103 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -1109,6 +1109,12 @@ out: } #ifdef CONFIG_SECCOMP_FILTER +static void seccomp_notify_free(struct seccomp_filter *filter) +{ + kfree(filter->notif); + filter->notif = NULL; +} + static void seccomp_notify_detach(struct seccomp_filter *filter) { struct seccomp_knotif *knotif; @@ -1138,8 +1144,7 @@ static void seccomp_notify_detach(struct seccomp_filter *filter) complete(&knotif->ready); } - kfree(filter->notif); - filter->notif = NULL; + seccomp_notify_free(filter); mutex_unlock(&filter->notify_lock); } @@ -1494,7 +1499,7 @@ static struct file *init_listener(struct seccomp_filter *filter) out_notif: if (IS_ERR(ret)) - kfree(filter->notif); + seccomp_notify_free(filter); out: return ret; } -- cgit v1.2.3 From 40249c6962075c040fd071339acae524f18bfac9 Mon Sep 17 00:00:00 2001 From: Peter Oberparleiter Date: Thu, 10 Sep 2020 14:52:01 +0200 Subject: gcov: add support for GCC 10.1 Using gcov to collect coverage data for kernels compiled with GCC 10.1 causes random malfunctions and kernel crashes. This is the result of a changed GCOV_COUNTERS value in GCC 10.1 that causes a mismatch between the layout of the gcov_info structure created by GCC profiling code and the related structure used by the kernel. Fix this by updating the in-kernel GCOV_COUNTERS value. Also re-enable config GCOV_KERNEL for use with GCC 10. Reported-by: Colin Ian King Reported-by: Leon Romanovsky Signed-off-by: Peter Oberparleiter Tested-by: Leon Romanovsky Tested-and-Acked-by: Colin Ian King Signed-off-by: Linus Torvalds --- kernel/gcov/Kconfig | 1 - kernel/gcov/gcc_4_7.c | 4 +++- 2 files changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig index bb4b680e8455..3110c77230c7 100644 --- a/kernel/gcov/Kconfig +++ b/kernel/gcov/Kconfig @@ -4,7 +4,6 @@ menu "GCOV-based kernel profiling" config GCOV_KERNEL bool "Enable gcov-based kernel profiling" depends on DEBUG_FS - depends on !CC_IS_GCC || GCC_VERSION < 100000 select CONSTRUCTORS if !UML default n help diff --git a/kernel/gcov/gcc_4_7.c b/kernel/gcov/gcc_4_7.c index 908fdf5098c3..53c67c87f141 100644 --- a/kernel/gcov/gcc_4_7.c +++ b/kernel/gcov/gcc_4_7.c @@ -19,7 +19,9 @@ #include #include "gcov.h" -#if (__GNUC__ >= 7) +#if (__GNUC__ >= 10) +#define GCOV_COUNTERS 8 +#elif (__GNUC__ >= 7) #define GCOV_COUNTERS 9 #elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1) #define GCOV_COUNTERS 10 -- cgit v1.2.3