* Davidlohr Bueso <dave@xxxxxxxxxxxx> [2014-10-24 15:06:15]: > Both register and unregister call build_map_info() in order > to create the list of mappings before installing or removing > breakpoints for every mm which maps file backed memory. As > such, there is no reason to hold the i_mmap_rwsem exclusively, > so share it and allow concurrent readers to build the mapping > data. > > Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx> Copying Oleg (since he should have been copied on this one) Please see one comment below. Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx> > --- > kernel/events/uprobes.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index 045b649..7a9e620 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -724,7 +724,7 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register) > int more = 0; > > again: > - i_mmap_lock_write(mapping); > + i_mmap_lock_read(mapping); > vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) { > if (!valid_vma(vma, is_register)) > continue; Just after this, we have if (!prev && !more) { /* * Needs GFP_NOWAIT to avoid i_mmap_mutex recursion through * reclaim. This is optimistic, no harm done if it fails. */ prev = kmalloc(sizeof(struct map_info), GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN); if (prev) prev->next = NULL; } However in patch 02/10 I dont think the comment referring to i_mmap_mutex was modified to refer i_mmap_lock_write. When thats taken care off, this patch should change that part accordingly. -- Thanks and Regards Srikar Dronamraju -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>