6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook <kees@xxxxxxxxxx> [ Upstream commit 200f091c95bbc4b8660636bd345805c45d6eced7 ] The 'comm' member will always be NUL terminated, and this is not fast-path, so we can just perform a direct memcpy during a coredump instead of potentially deadlocking while holding the task struct lock. Reported-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx> Closes: https://lore.kernel.org/all/d122ece6-3606-49de-ae4d-8da88846bef2@xxxxxxxxxx Fixes: c114e9948c2b ("coredump: Standartize and fix logging") Tested-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx> Link: https://lore.kernel.org/r/20240928210830.work.307-kees@xxxxxxxxxx Signed-off-by: Kees Cook <kees@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- include/linux/coredump.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/coredump.h b/include/linux/coredump.h index 45e598fe34766..77e6e195d1d68 100644 --- a/include/linux/coredump.h +++ b/include/linux/coredump.h @@ -52,8 +52,8 @@ extern void do_coredump(const kernel_siginfo_t *siginfo); #define __COREDUMP_PRINTK(Level, Format, ...) \ do { \ char comm[TASK_COMM_LEN]; \ - \ - get_task_comm(comm, current); \ + /* This will always be NUL terminated. */ \ + memcpy(comm, current->comm, sizeof(comm)); \ printk_ratelimited(Level "coredump: %d(%*pE): " Format "\n", \ task_tgid_vnr(current), (int)strlen(comm), comm, ##__VA_ARGS__); \ } while (0) \ -- 2.39.5
