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    Subject[v6.7][PATCH v2 10/23] eventfs: Use kcalloc() instead of kzalloc()
    From: Erick Archer <erick.archer@gmx.com>

    As noted in the "Deprecated Interfaces, Language Features, Attributes,
    and Conventions" documentation [1], size calculations (especially
    multiplication) should not be performed in memory allocator (or similar)
    function arguments due to the risk of them overflowing. This could lead
    to values wrapping around and a smaller allocation being made than the
    caller was expecting. Using those allocations could lead to linear
    overflows of heap memory and other misbehaviors.

    So, use the purpose specific kcalloc() function instead of the argument
    size * count in the kzalloc() function.

    [1] https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments

    Link: https://lore.kernel.org/linux-trace-kernel/20240115181658.4562-1-erick.archer@gmx.com

    Cc: Masami Hiramatsu <mhiramat@kernel.org>
    Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
    Cc: Mark Rutland <mark.rutland@arm.com>
    Link: https://github.com/KSPP/linux/issues/162
    Signed-off-by: Erick Archer <erick.archer@gmx.com>
    Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
    Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
    (cherry picked from commit 1057066009c4325bb1d8430c9274894d0860e7c3)
    ---
    fs/tracefs/event_inode.c | 6 +++---
    1 file changed, 3 insertions(+), 3 deletions(-)

    diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
    index 10580d6b5012..6795fda2af19 100644
    --- a/fs/tracefs/event_inode.c
    +++ b/fs/tracefs/event_inode.c
    @@ -97,7 +97,7 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
    /* Preallocate the children mode array if necessary */
    if (!(dentry->d_inode->i_mode & S_IFDIR)) {
    if (!ei->entry_attrs) {
    - ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries,
    + ei->entry_attrs = kcalloc(ei->nr_entries, sizeof(*ei->entry_attrs),
    GFP_NOFS);
    if (!ei->entry_attrs) {
    ret = -ENOMEM;
    @@ -874,7 +874,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
    }

    if (size) {
    - ei->d_children = kzalloc(sizeof(*ei->d_children) * size, GFP_KERNEL);
    + ei->d_children = kcalloc(size, sizeof(*ei->d_children), GFP_KERNEL);
    if (!ei->d_children) {
    kfree_const(ei->name);
    kfree(ei);
    @@ -941,7 +941,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
    goto fail;

    if (size) {
    - ei->d_children = kzalloc(sizeof(*ei->d_children) * size, GFP_KERNEL);
    + ei->d_children = kcalloc(size, sizeof(*ei->d_children), GFP_KERNEL);
    if (!ei->d_children)
    goto fail;
    }
    --
    2.43.0


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